CN101360190A - Imaging device, and control method for imaging device - Google Patents

Abstract

An imaging device comprising an imaging unit for receiving subject light flux, incident via a photographing lens, on an imaging surface, and photoelectrically converting a subject image that has been formed on the imaging surface to output subject image data; a display unit for carrying out a live view display operation using the subject image data; a first contrast AF unit that obtains contrast information of the subject image from subject image data, and guides the photographing lens to within a first focus permissible based on the contrast information; a phase difference AF unit for placing the movable mirror in the optical path of the photographing lens, receiving subject light flux reflected by the movable mirror to detect a defocus amount of the photographing lens by the phase difference method, and guiding the photographing lens to within a third in-focus permissible range in response to the detection results; a release button having a two stage operating arrangement of half pressed and fully pressed; and a control unit for, when the release button has been pressed down halfway during execution of the live view display operation, executing a focusing operation using the first contrast AF unit, and after that, when the release button is pressed down fully, executing a focusing operation using the phase contrast AF unit.

Description

Image capturing apparatus and control method of image capturing apparatus

Technical Field

The present invention relates to a digital camera having a Live View (Live View) display function, and more particularly, to an imaging apparatus having a so-called Live View display function (also referred to as an electronic viewfinder function) for displaying an image acquired by an imaging device on a display device, and capable of adjusting the focus of an imaging lens using an image signal during the Live View display, and a method for controlling the imaging apparatus.

Background

In a conventional digital camera, an object image is observed through an optical viewfinder. However, recently, a digital camera having a live view display function for observing an object image by displaying an image acquired by an image pickup element on a display device such as a liquid crystal monitor without using an optical finder or together with the optical finder is commercially available.

Such a digital camera having a live view display function is easy and convenient to observe because it directly displays an object image acquired by an imaging element. However, in a digital single lens reflex camera (digital monocular reflex camera), since a movable mirror disposed in a photographing optical path is temporarily retracted out of the optical path in order to perform live view display, the following conventional phase difference AF (Auto focus) mechanism cannot be used in live view display: the defocus amount of the photographing lens is detected using the subject light beam reflected by a sub-mirror attached to a movable mirror.

For example, japanese laid-open patent publication No. 2001-281530 (published 10/2001) discloses a digital single lens reflex camera that performs AF by using both contrast AF that detects contrast information from an image signal from an image pickup element and phase difference AF. When the digital single lens reflex camera performs live view display, focusing of a photographing lens is performed only by contrast AF.

In this way, in a digital single lens reflex camera that performs live view display, when focus adjustment is performed by normal contrast AF, the following problems arise. That is, the contrast AF is also called a hill-climbing method, and it takes time to focus because it is necessary to search for a point at which the contrast value of the image output is maximum and move the photographing lens forward and backward. In addition, in the lens-interchangeable single lens reflex camera, since it is necessary to notify contrast information of an image signal to the photographing lens for each frame, the number of communications increases and it takes time to perform focusing in order to improve focusing accuracy. Further, some of the photographing lenses have a large feed amount from the infinite end, such as a macro lens, and in this case, the focusing time is also extended.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an imaging apparatus and a control method of the imaging apparatus, which can perform focus adjustment with less delay and high accuracy when performing imaging from a live view display state.

The imaging device of the present invention includes: an image pickup device that receives an object light beam incident via a photographing lens on an image pickup surface, photoelectrically converts an object image formed on the image pickup surface, and outputs object image data; a display device that performs a live view display operation using the subject image data acquired by the imaging device; a 1 st contrast AF device that obtains contrast information of the subject image from the subject image data and introduces the photographing lens into a 1 st focus allowable range based on the contrast information; a phase difference AF device that receives the subject light beam reflected by the mirror member, the mirror member being disposed in an optical path of the photographing lens, detects a defocus amount of the photographing lens in a phase difference manner, and guides the photographing lens to a 3 rd focus allowable range based on a detection result; a release button having a 2-stage operation manner of a half-press operation and a full-press operation; and a control device that performs control to cause the 1 st contrast AF device to perform a focus adjustment operation when a half-press operation of a release button is performed during execution of the live view display operation, and thereafter to cause the phase difference AF device to perform the focus adjustment operation when a full-press operation of the release button is performed.

Further, a control method of an imaging apparatus according to the present invention includes: shooting a subject; performing live view display of the captured subject image; according to the preparation operation of shooting, the contrast information according to the above-mentioned object picture guides the photographic lens into the 1 st focusing and allows the range; and according to the shooting operation, the shooting lens is guided into the 3 rd focusing allowable range according to the defocusing information of the shooting lens.

Further, a control method of an imaging apparatus according to the present invention includes: shooting a subject; performing live view display of the captured subject image; according to the preparation operation of shooting, the contrast information according to the above-mentioned object picture guides the photographic lens into the 1 st focusing and allows the range; and when the photographing preparation operation is continued and the photographing operation is not performed, the photographing lens is guided into the 2 nd focusing allowable range according to the contrast information of the object image.

Drawings

Fig. 1 is an external perspective view of a digital single lens reflex camera according to embodiment 1 of the present invention, as viewed from the rear.

Fig. 2 is a block diagram showing the overall configuration of the digital single lens reflex camera according to embodiment 1 to which the present invention is applied.

Fig. 3 is a flowchart showing a power-on reset operation on the camera body side in embodiment 1 of the present invention.

Fig. 4 is a flowchart showing a live view display operation in embodiment 1 of the present invention.

Fig. 5 is a flowchart showing a live view display operation in embodiment 1 of the present invention.

Fig. 6 is a flowchart showing a live view display operation in embodiment 1 of the present invention.

Fig. 7 is a flowchart showing the operation of the photographing operation a in embodiment 1 of the present invention.

Fig. 8 is a flowchart showing the operation of the photographing operation B in embodiment 1 of the present invention.

Fig. 9 is a flowchart showing a phase difference AF control operation in embodiment 1 of the present invention.

Fig. 10 is a flowchart showing a contrast AF control operation in embodiment 1 of the present invention.

Fig. 11 is a flowchart showing a contrast AF control operation in embodiment 1 of the present invention.

Fig. 12 is a flowchart showing the power-on reset operation on the replacement lens side in embodiment 1 of the present invention.

Fig. 13A to 13E are diagrams showing a display state on a liquid crystal monitor in an enlarged display mode in embodiment 1 of the present invention, fig. 13A is a diagram showing a full-screen display state, fig. 13B is a diagram showing an enlarged display state, fig. 13C is a diagram showing a state after an enlargement range is moved, fig. 13D is a diagram showing an enlarged portion in fig. 13B, and fig. 13E is a diagram showing an enlarged portion in fig. 13C.

Fig. 14 is a diagram showing a menu display screen for AF mode setting in embodiment 1 of the present invention.

Fig. 15A to 15B are views showing a display at the time of completion of focusing in embodiment 1 of the present invention, fig. 15A is a view showing a 1 st focus display, and fig. 15B is a view showing a 2 nd focus display.

Fig. 16A to 16B are diagrams showing a driving relationship between contrast information and a focus lens in embodiment 1 of the present invention, fig. 16A is a diagram showing a case of high-speed contrast AF, and fig. 16B is a diagram showing a case of high-precision contrast AF.

Fig. 17A to 17B are diagrams for explaining the allowable circle of confusion of the image pickup device and the liquid crystal monitor according to embodiment 1 of the present invention, in which fig. 17A shows the allowable circle of confusion of the image pickup device, and fig. 17B shows the allowable circle of confusion of the liquid crystal monitor.

Fig. 18 is a diagram showing a relationship between an allowable circle diameter of confusion and a defocus amount in embodiment 1 of the present invention.

Fig. 19 is a flowchart showing a live view display operation in embodiment 2 of the present invention.

Fig. 20 is a flowchart showing a phase difference AF control operation in embodiment 2 of the present invention.

Fig. 21 is a flowchart showing a contrast AF control operation in embodiment 2 of the present invention.

Fig. 22 is a flowchart showing a contrast AF control operation in embodiment 2 of the present invention.

Fig. 23 is a diagram conceptually showing the relationship between the focus detection point and the zoom level in embodiment 2 of the present invention.

Fig. 24 is a flowchart showing a power-on reset operation on the camera body side in embodiment 3 of the present invention.

Fig. 25 is a flowchart showing a live view display operation in embodiment 3 of the present invention.

Fig. 26 is a flowchart showing the live view display operation in embodiment 3 of the present invention.

Fig. 27 is a flowchart showing the live view display operation in embodiment 3 of the present invention.

Fig. 28 is a flowchart showing a contrast AF control operation in embodiment 3 of the present invention.

Fig. 29 is a flowchart showing a contrast AF control operation in embodiment 3 of the present invention.

Detailed Description

Hereinafter, preferred embodiments will be described with reference to the drawings using a digital single lens reflex camera according to the present invention. Fig. 1 is an external perspective view of a digital single lens reflex camera according to embodiment 1 of the present invention, as viewed from the rear.

A release button 21, a shooting mode dial 22, an information setting dial 24, a flash 50, and the like are provided on the upper surface of the camera body 200. The release button 21 has a 1 st release switch that is turned on when the photographer half-presses and a 2 nd release switch that is turned on when fully pressing. The camera performs a photographing preparation operation such as focus detection, focusing of a photographing lens, and photometry of subject luminance by turning on the 1 st release switch (hereinafter, referred to as a "1R" photographing preparation operation), and performs a photographing operation for acquiring image data of a subject image based on an output of the image pickup device 221 with reference to fig. 2 by turning on the 2 nd release switch (hereinafter, referred to as a "2R" photographing operation).

The photography mode dial 22 is a rotatable operation member, and by matching a picture display or a symbol indicating a photography mode provided on the photography mode dial 22 with a pointer, various photography modes such as a full-automatic photography mode (AUTO), a program photography mode (P), a diaphragm priority photography mode (a), a shutter photography priority mode (S), a manual photography mode (M), a portrait photography mode, a landscape photography mode, a close-up photography mode, a sport photography mode, and a night view photography mode can be selected.

The information setting dial 24 is an operation member configured to be rotatable, and a desired setting value, a desired mode, or the like can be selected by rotating the information setting dial 24 on an information display screen or the like. The strobe 50 is a pop-up auxiliary lighting device, and by operating an operation button not shown, the strobe 50 can be popped up to irradiate the subject.

A liquid crystal monitor 26, a continuous shooting/single shooting button 27, an AF lock button 28, an upward cross button 30U, a downward cross button 30D, a rightward cross button 30R, a leftward cross button 30L (when these cross buttons 30U, 30D, 30R, 30L are collectively referred to, the cross button 30), an OK button 31, a live view display button 33, an enlargement button 34, a menu button 37, and a playback button 38 are disposed on the back surface of the camera body 200. The liquid crystal monitor 26 is a display device for performing live view display, reproducing and displaying a captured subject image, and displaying imaging conditions and menus. The display device is not limited to a liquid crystal display as long as it can perform such display.

The continuous shooting/single shooting button 27 is an operation member for switching between a continuous shooting mode in which shooting is continuously performed while the release button 21 is fully pressed and a single shooting mode in which 1 sheet is shot while the release button 21 is fully pressed. The AF lock button 28 is an operation member for fixing the focus of the subject. Thus, even if the composition is changed after the subject to be photographed is focused and the focus is fixed by operating the AF lock button 28 in this state, photographing in which the subject to be photographed is focused can be performed.

The cross button 30 is an operation member for instructing the liquid crystal monitor 26 to move the cursor in two-dimensional directions of the X direction and the Y direction, and the cross button 30 is also used for instructing selection of an object image when reproducing and displaying the object image recorded in the recording medium 277 (see fig. 2). In addition, the cross button 30 can be replaced with a touch switch, in addition to 4 buttons for up, down, left, and right. The OK button 31 is an operation member for determining various items selected using the cross button 30, the control dial 24, and the like.

The live view display button 33 is an operation button for switching from a display screen for information display or the like to live view display, and from live view display to a display screen for information display or the like. The live view display is a mode in which the subject image is displayed on the liquid crystal monitor 26 for observation based on the output of the image pickup device 221 for subject image recording, and the information display is a mode in which the shooting information of the digital camera is displayed on the liquid crystal monitor 26. The zoom-in button 34 is an operation member for displaying a part of the subject image on the liquid crystal monitor 26 in a zoomed-in manner, and the zoom-in position can be changed by operating the cross button 30.

The menu button 37 is an operation member for switching to a menu mode for setting various modes of the digital camera, and when the menu mode is selected by operating the menu button 37, a menu screen is displayed on the liquid crystal monitor 26. The menu screen has a hierarchical structure, and various items are selected by the cross button 30, and selection is determined by operating the OK button 31. The reproduction button 38 is an operation button for instructing to display the recorded object image on the liquid crystal monitor 26 after the photographing. When a reproduction display instruction is given, image data of a subject stored in a compression mode such as JPEG in an SDRAM (synchronous dynamic memory) 267 described later and a recording medium 277 is decompressed and displayed.

A recording medium storage cover 40 is openably and closably attached to a side surface of the camera body 200. A slot for loading the recording medium 277 when the recording medium storage cover 40 is opened is provided inside the recording medium storage cover 40, and the recording medium 277 can be loaded into and removed from the camera body 200.

Next, the overall configuration of the digital single lens reflex camera, mainly the electric system, will be described with reference to fig. 2. The digital single lens reflex camera of the present embodiment is composed of an interchangeable lens 100 and a camera body 200. In the present embodiment, the interchangeable lens 100 and the camera body 200 are separately configured and electrically connected by the communication contact 300, but the interchangeable lens 100 and the camera body 200 may be configured integrally. In addition, a circuit block diagram of the built-in flash 50 is omitted in fig. 2.

Inside the interchangeable lens 100, a photographing optical system 101 for focus adjustment and a diaphragm 103 for adjusting a numerical aperture are arranged. The photographing optical system 101 is connected to: the diaphragm 103 is driven by a diaphragm driving mechanism 109, while being driven by an optical system driving mechanism 107. The focal length and the focal position of the photographing optical system 101 driven by the optical system driving mechanism 107 are detected by the optical system position detecting mechanism 105.

The optical system driving mechanism 107, the diaphragm driving mechanism 109, and the optical system position detecting mechanism 105 are connected to a lens CPU111, respectively, and the lens CPU111 is connected to the camera body 200 via a communication contact 300. The lens CPU111 performs control in the interchangeable lens 100, performs focus and zoom driving by controlling the optical system driving mechanism 107, and performs aperture value control by controlling the aperture driving mechanism 109. Also, the lens CPU111 transmits the focal length and focal position information detected by the optical system position detection mechanism 105 to the camera body 200.

A movable mirror 201 is provided in the camera body 200, and the movable mirror 201 is rotatable between a position (a lowered position, an object image observation position) inclined by 45 degrees with respect to the lens optical axis in order to reflect an object image to the observation optical system and a position (a raised position, a retracted position) raised in order to introduce the object image to the image pickup element 221. A focusing screen 205 for forming an object image is disposed above the movable mirror 201, and a pentaprism 207 for inverting the object image in the left-right direction is disposed above the focusing screen 205.

An eyepiece (not shown) for observing an object image is disposed on the light emission side (right side in fig. 2) of the pentaprism 207, and a photometric sensor 211 is disposed on the side surface thereof at a position that does not interfere with the observation of the object image. The photometry sensor 211 is connected to a photometry processing circuit 241, and the output of the photometry sensor 211 is subjected to amplification processing, analog-to-digital conversion, and the like by the photometry processing circuit 241.

The movable mirror 201 is constituted by a half mirror in the vicinity of the center thereof, and a sub-mirror 203 is provided on the rear surface of the movable mirror 201, the sub-mirror 203 reflecting the subject light transmitted through the half mirror to the lower part of the camera body 200. The sub mirror 203 is rotatable with respect to the movable mirror 201, and when the movable mirror 201 is lifted up (the broken line position in fig. 2), the sub mirror 203 is rotated to a position covering the half mirror portion, and when the movable mirror 201 is positioned at a position (lowered position) where an object image is observed, the sub mirror 203 is positioned at a position opened with respect to the movable mirror 201 as shown in the drawing.

The movable mirror 201 is driven by a movable mirror driving mechanism 239. A phase difference AF sensor 243 is disposed below the sub mirror 203, and the output of the phase difference AF sensor 243 is connected to a phase difference AF processing circuit 245. The phase difference AF sensor 243 is configured by a known phase difference AF optical system that separates peripheral light beams of the photographing optical system 101 into 2 light beams and a 1-pair sensor in order to measure a defocus amount of an object image imaged by the photographing optical system 101. The phase difference AF sensor 243 can detect the focus of each of a plurality of points in the image capture screen.

A focal plane shutter 213 for controlling exposure time is disposed behind the movable mirror 201, and the shutter 213 is driven and controlled by a shutter drive mechanism 237. An image pickup element 221 is disposed behind the shutter 213, and the image pickup element 221 photoelectrically converts an object image formed by the photographing optical system 101 into an electric signal. As the image pickup Device 211, a two-dimensional image pickup Device such as a CCD (Charge Coupled Device) or a CMOS (Complementary metal oxide Semiconductor) may be used.

The image pickup device 221 is connected to an image pickup device drive circuit 223, and image signals are read from the image pickup device 221 by the image pickup device drive circuit 223. The image pickup device driving circuit 223 is connected to a preprocessing circuit 225, and the preprocessing circuit 225 performs preprocessing for image processing such as pixel thinning processing for live view display and clipping processing for enlarged display.

A dust filter 215, a piezoelectric element 216, and an infrared cut filter/low pass filter 217 are disposed between the shutter 213 and the image pickup element 221. A piezoelectric element 216 is fixed around the dust-proof filter 215, and the piezoelectric element 216 is ultrasonically vibrated by a dust-proof filter drive circuit 235. The dust attached to the dust filter 215 is removed by the vibration wave generated by the piezoelectric element 216.

The infrared cut filter/low pass filter 217 is a filter for removing an infrared light component and a high frequency component from the subject light beam. The dust-proof filter 215, the piezoelectric element 216, the infrared cut filter/low pass filter 217, and the image pickup element 221 are integrated in an airtight manner so that dust and the like do not enter. The integrated image pickup device 221 and the like can be moved by the moving mechanism 233 along the X-axis direction and the Y-axis direction on the image pickup surface of the image pickup device 221.

The camera shake sensor 227 is a sensor for detecting vibrations such as camera shake applied to the camera body 200, and the output of the camera shake sensor 227 is connected to the camera shake correction circuit 229. The camera shake correction circuit 229 generates a camera shake correction signal for removing vibrations such as camera shake, and the output of the camera shake correction circuit 229 is connected to the movement mechanism drive circuit 231. The moving mechanism driving circuit 231 inputs the handshake correction signal and drives the moving mechanism 233 according to the signal. The image pickup device 221 and the like are moved by the moving mechanism 233 to prevent shaking and to eliminate vibration such as hand shake applied to the camera body 200.

The preprocessing Circuit 225 is connected to a data bus 252 within an ASIC (Application Specific Integrated Circuit) 250. A sequence controller (hereinafter referred to as "main body CPU") 251, an image processing circuit 257, a compression/decompression circuit 259, a video signal output circuit 261, an SDRAM control circuit 265, an input/output circuit 271, a communication circuit 273, a recording medium control circuit 275, a flash memory control circuit 279, and a switch detection circuit 283 are connected to the data bus 252.

A main body CPU251 connected to a data bus 252 controls the operation of the digital single lens reflex camera. A contrast AF circuit 253 and an AE circuit 255 are connected in parallel between the preprocessing circuit 225 and the main body CPU 251. The contrast AF circuit 253 extracts a high-frequency component from the image signal output from the preprocessing circuit 225, and outputs contrast information based on the high-frequency component to the main body CPU 251. The AE circuit 255 outputs photometric information corresponding to the subject luminance to the main body CPU251 based on the image signal output from the preprocessing circuit 225.

The image processing circuit 257 connected to the data bus 252 performs various image processes such as digital amplification (digital gain adjustment process) of digital image data, color correction, gamma (γ) correction, contrast correction, and image generation for live view display. The compression/decompression circuit 259 is a circuit for compressing the image data stored in the SDRAM 267 by a compression method such as JPEG or TIFF. The image compression is not limited to JPEG and TIFF, and other compression methods may be applied.

The video signal output circuit 261 is connected to the liquid crystal monitor 26 via a liquid crystal monitor drive circuit 263. The video signal output circuit 261 is a circuit for converting image data stored in the SDRAM 267 and the recording medium 277 into a video signal for display on the liquid crystal monitor 26. As shown in fig. 1, the liquid crystal monitor 26 is disposed on the back surface of the camera body 200, but is not limited to the back surface and is not limited to a liquid crystal display, and may be another display device as long as it can be observed by a photographer.

The SDRAM 267 is a buffer memory for temporarily storing image data subjected to image processing by the image processing circuit 257 or image data compressed by the compression/decompression circuit 259, and is connected to the data bus 261 via an SDRAM control circuit 265.

An input/output circuit 271 connected to the image pickup device drive circuit 223, the preprocessing circuit 225, the camera shake correction circuit 229, the movement mechanism drive circuit 231, the dust filter drive circuit 235, the shutter drive mechanism 237, the movable mirror drive mechanism 239, the photometry processing circuit 241, and the phase difference AF processing circuit 245 controls data input/output with respect to the respective circuits such as the main body CPU251 via a data bus 252.

A communication circuit 273 connected to the lens CPU111 via the communication contact 300 is connected to the data bus 252, and performs data exchange with the main body CPU251 and the like and communication of control commands. A recording medium control circuit 275 connected to the data bus 252 is connected to a recording medium 277, and controls recording of image data and the like and reading of image data and the like in the recording medium 277.

The recording medium 277 is configured to be loaded with any of rewritable recording media such as an XD Picture Card (registered trademark), a Flash Memory Card (registered trademark), an SD Memory Card (registered trademark), and a Memory Stick (registered trademark), and is detachable from the camera body 200. Further, the hard disk drive may be connected to the hard disk drive via a communication contact.

The Flash Memory control circuit 279 is connected to a Flash Memory 281 (Flash Memory)281, the Flash Memory 281 stores a program for controlling the operation of the digital single lens reflex camera, and the main CPU251 controls the digital single lens reflex camera according to the program stored in the Flash Memory 281. The flash memory 281 is an electrically rewritable nonvolatile memory.

Various switches 285 including a 1R switch that detects the 1 st stroke (half-press) of the shutter release button 21, a 2R switch that detects the 2 nd stroke (full-press), and a live view display switch that is turned on by the operation of the live view display button 33 are connected to the data bus 252 via a switch detection circuit 283. The various switches 285 include an enlargement switch linked to the enlargement button 34, a power switch, a menu switch linked to the menu button 37, an AF lock switch linked to the AF lock button 28, a continuous/single shot switch linked to the continuous/single shot button 27, and other various switches linked to other operation members.

Next, the operation of the digital camera according to embodiment 1 of the present invention will be described with reference to flowcharts shown in fig. 3 to 12. Fig. 3 shows a power-on reset operation of the main body CPU251 on the camera main body 200 side. When the camera body 200 is loaded with a battery, the flow starts, and it is first determined whether or not the power switch of the camera body 200 is turned on (# 1).

If the power switch is off as a result of the determination, the power switch is in a low power consumption state, i.e., a sleep state (# 3). In this sleep state, the interrupt processing is performed only when the power switch is turned on, and the processing for turning on the power switch is performed in steps #5 and below. Before the power switch is turned on, operations other than the power switch off processing are stopped, thereby preventing the consumption of the power battery.

In step #1, when the power switch is turned on or when the sleep state in step #3 is released, power supply is started (# 5). Then, the dust removing operation in the dust-proof filter 215 is performed (# 7). This is an operation of applying a driving voltage from the dust-proof filter driving circuit 235 to the piezoelectric element 216 fixed to the dust-proof filter 215 and removing dust and the like by ultrasonic vibration waves.

When the program shooting mode set by the shooting mode dial 22 or the like, the shooting mode such as the close-up shooting mode, the ISO sensitivity, and the manually set shutter speed and aperture value are included, the shooting conditions and the lens information are read (# 9). The lens information is read from the lens CPU111 via the communication circuit 273, and the lens characteristic information such as the open stop, the focal length information, the lens identification number, and the type of the interchangeable lens such as the macro lens of the interchangeable lens 100 is read.

Next, photometry and exposure amount calculation are performed (# 11). In this step, the subject luminance is photometered by the photometry sensor 211, an exposure amount is calculated, and exposure control values such as a shutter speed and an aperture value are calculated in accordance with a photographing mode/photographing condition using the exposure amount. Then, the image pickup information is displayed on the liquid crystal monitor 26 (# 13). The imaging information includes the imaging mode and imaging conditions read in step #9, and the exposure control values of the shutter speed and aperture value calculated in step # 11.

Then, it is determined whether or not the live view display switch is on (# 15). As described above, in the case where the photographer observes the subject image by the live view display, the live view display button 33 is operated. If the live view display switch is on as a result of the determination, a subroutine of the live view display operation is executed (# 31). This live view display operation will be described later using fig. 4 to 6.

If the live view display switch is not turned on as a result of the determination in step #15, it is determined whether or not the reproduction switch is turned on (# 17). The playback mode is a mode in which still image data recorded in the recording medium 277 is read and displayed on the liquid crystal monitor 26 when the playback button 38 is operated. If the determination result is that the reproduction switch is on, the reproduction operation is executed (# 33).

If the playback switch is not turned on as a result of the determination in step #17, it is determined whether or not the menu switch is turned on (# 19). In this step, it is determined whether or not the menu button 37 is operated and the menu mode is set. If the menu switch is turned on as a result of the determination, the menu is displayed on the liquid crystal monitor 26, and the menu setting operation is performed (# 35). Various setting operations such as an AF mode, a white balance, an ISO sensitivity setting, and a drive mode can be performed by the menu setting operation.

If the menu switch is not turned on as a result of the determination in step #19, it is determined whether the release button 21 is half pressed (shooting preparation operation), that is, whether the 1R switch is turned on (# 21). If the 1R switch is turned on as a result of the determination, a subroutine of the photographing operation a for preparing for photographing and photographing is executed (# 37). Details of this subroutine are described later using fig. 7.

If the 1R switch is not turned on as a result of the determination in step #21, it is determined whether or not the power switch is turned on (#23) as in step # 1. If the power switch is turned on as a result of the determination, the process returns to step #9 to repeat the above operation. On the other hand, if the power switch is not turned on, the power supply is stopped (#25), and the process returns to step #3, and the sleep state described above is set.

Next, the live view display operation in step #31 will be described with reference to fig. 4 to 6. When the subroutine is entered, first, the photographing information display is turned off (# 41). In step #13, the image pickup information is displayed on the liquid crystal monitor 26, and in this step, the display of the image pickup information is stopped in order to display the live view on the liquid crystal monitor 26. Next, as in step #11, metering and exposure amount calculation is performed (# 43).

Then, the movable mirror 201 is retracted from the optical axis of the photographing optical system 101 (#45), and the shutter 213 is opened (# 47). By these operations, the subject image of the photographing optical system 101 is formed on the image pickup element 221. Next, the live view conditions are initially set (# 49). In this step, in order to perform condition setting of the electronic shutter speed and sensitivity when the image pickup device 221 is driven, calculation and setting for displaying an image of appropriate brightness (brightness) on the liquid crystal monitor 26 are performed using the calculation results of the metering and exposure amounts obtained in step # 43.

Then, the start of live view display is instructed (# 51). That is, the image pickup device 221, the image processing circuit 257, and the like are instructed to display image data acquired by the image pickup device 221 on the liquid crystal monitor 26 as a moving image. The photographer can decide a photographing composition based on the live view display. In the live view display, the electronic shutter speed, ISO sensitivity, and the like are controlled so that the screen brightness of the liquid crystal monitor 26 is constant.

When the live view display is started, it is next determined whether the release button 21 is half pressed, that is, whether the 1R switch is on (# 53). If the determination result is that the 1R switch is not on, it is determined whether the enlargement button 34 is operated, that is, whether the enlargement switch is on (# 55). If the determination result is that the enlargement switch is not on, the routine proceeds to step #71 (fig. 5), whereas if the enlargement switch is on, it is determined whether or not the enlarged display is being displayed (# 57).

As described above, the zoom-in button 34 is an operation button for displaying the subject image in the live view display mode in a magnified manner, and when the operation is performed once, the zoom-in display mode is set, and when the operation is performed again, the zoom-in display mode is released. Therefore, in step #57, it is determined whether to continue execution or end the enlargement display mode.

If the determination result in step #57 is not in the enlarged display mode, that is, if the mode is changed from the non-enlarged display mode (normal live view display mode) to the enlarged display mode, an instruction to cut out the range is given (#59), and the start of the enlarged display is instructed (# 61). The enlargement display is performed such that: the preprocessing circuit 225 is instructed to cut out image data corresponding to the enlargement range from the image data read out by the image pickup element 221.

If the determination result in step #57 is that the enlarged display is in progress, processing for ending the enlarged display mode and returning to the normal live view display is performed. That is, an instruction to output a full screen to the preprocessing circuit 225 is given (#63), and an instruction to stop the enlarged display to the image processing circuit 257 is given (# 65). When the processing of step #61 or #65 is finished, the process proceeds to step #71, and it is determined whether or not the operation of the cross button 30 is performed.

If the result of determination in step #71 is that the cross button 30 is operated, it is next determined whether or not the enlarged display is in progress (# 73). If the determination result in both of step #71 and step #73 is "no", the process proceeds to step #77, and if the determination result in both steps is "yes", that is, if the enlarged display is being displayed and the cross switch is operated, the movement of the enlarged area corresponding to the cross button 30 is instructed (# 75).

As described above, in the present embodiment, when the live view display mode is entered, as shown in fig. 13(a), the subject image is displayed in full screen on the liquid crystal monitor 26 (# 51). In this state, when the enlargement button 34 is operated (#55), as shown in fig. 13(B), the subject image is enlarged and displayed (# 61). As shown in fig. 13(D), the enlarged display is a part of the full screen display. Thereafter, when the cross button 30 is operated (#71), the position corresponding to the operation of the cross button 30 is enlarged and displayed (# 75). As shown in fig. 13(E), the enlarged display at this time corresponds to a position corresponding to the operation of the cross button 30 in a part of the full screen display.

Then, it is determined whether or not the live view display switch linked with the live view display button 33 is turned on (# 77). When the live view display button 33 is operated once, the live view display mode is set, and when it is operated again, the live view display mode is released. If the determination result in step #77 is on, the live view display mode ends below step # 85.

If the live view display switch is not turned on as a result of the determination in step #77, it is determined whether or not the playback switch linked to the playback button 38 is turned on (# 79). Since the reproduction display of the image data recorded in the recording medium 277 is performed on the liquid crystal monitor 26, it is necessary to end the live view display mode. If the determination result in step #79 is on, the live view display mode is ended in step #85 or less.

If the playback switch is not turned on as a result of the determination in step #79, it is determined whether or not the menu switch associated with the menu button 37 is turned on (# 81). Since the menu display is performed on the liquid crystal monitor 26, the live view display mode needs to be terminated. If the determination result in step #81 is on, the live view display mode is ended in step #85 or less.

If the menu switch is not turned on as a result of the determination in step #81, it is determined whether or not the power switch is turned on (# 83). When the power switch is off as a result of the determination, the live view display is first ended at step #85 or less because the power-off process is performed. When the determination result in step #83 is on, the process returns to step #53, and the above operation is repeated.

To end the live view display, when the process proceeds to step #85, the light is turned off for focus display (# 85). As described later, after the subject is focused, as shown in fig. 15A and 15B, the 1 st focus display 311 and the 2 nd focus display 312 are displayed, and therefore, when the focus display is performed, the display is turned off. Next, a stop instruction for live view display is given to the preprocessing circuit 225, the image processing circuit 257, and the like (# 87). Thereafter, a shutter closing operation is instructed to the shutter 213(# 89), and the movable mirror 201 is returned to the original program by performing a return operation (moving to the lowered position) (# 91).

If the 1R switch is turned on as a result of the determination in step #53 (fig. 4), AE information is read (#101, fig. 6). Since the movable mirror 201 is located at the down position, photometry in step #43 can be performed using the photometry sensor 211, whereas in this step, the movable mirror 201 is located at the backward position (up position) and photometry cannot be performed using the photometry sensor 211. Accordingly, the AE information is acquired from the output of the AE circuit 255.

Then, it is determined whether or not the mode is a phase difference AF only mode (# 103). The AF mode can be selected on the AF mode selection screen (see fig. 14) in the menu setting operation in step # 35. That is, in the present embodiment, any one of an i-AF mode in which only contrast AF based on the output of the image pickup element 221 is performed, a PD-AF mode in which only phase difference AF based on the output of the phase difference AF sensor 243 is performed, and an i-AF + PD-AF mode in which both contrast AF and phase difference AF are performed can be selected.

If the result of determination in step #103 is the phase difference AF only mode, the process proceeds to step #107, whereas if the result is not the phase difference AF only mode, contrast AF control is performed (# 105). In this contrast AF control, control is performed such that the photographing optical system 101 is in focus, based on contrast information from the contrast AF circuit 253. Details of this contrast AF control will be described later using fig. 10 and 11.

Then, it is determined whether or not the release button 21 is fully pressed (photographing operation), that is, whether or not the 2R switch is turned on (# 107). If the determination result is that the camera is not on, the process returns to step #53, and the operation such as the contrast AF control described above is repeated. On the other hand, when turned on, a photographing operation is performed below step # 109.

When the photographing operation is started, the live view display is first stopped (# 109). Next, the shutter 213 is closed (# 111). In the live view display, the shutter 213 is opened, and the subject image is displayed on the liquid crystal monitor 26 in accordance with the output of the image pickup device 221, but the shutter 213 is temporarily closed to enter the photographing operation.

Then, it is determined whether or not the focus display is in the 2 nd focus display (# 113). In the subroutine of the contrast AF control, the 1 st contrast AF control for introducing the photographing lens into the 1 st focus allowable range and the 2 nd contrast AF control for introducing the photographing lens into the 2 nd focus allowable range narrower than the 1 st focus allowable range are executed, and in the case where the 2 nd contrast AF control is ended, the 2 nd focus display is performed (#277 and 15B in fig. 11). In step #113, it is determined whether or not the high-precision 2 nd focus state is present.

If the focus display is not in the 2 nd focus display in step #113, it is determined whether or not the condition for not requiring the phase difference AF is satisfied (# 115). The condition that the phase difference AF is not required is a case where the subject scene depth is larger than the 1 st focusing allowable range for the following reasons (1) to (3), and the like: (1) the focal length of the photographing lens is on the wide-angle side with respect to a predetermined value, (2) the aperture value is equal to or greater than a predetermined value (the aperture diameter is small), and (3) the object distance is on the long-distance side which is longer than the predetermined distance. That is, when these conditions are satisfied, it is considered that sufficient focusing accuracy can be obtained by the 1 st contrast AF control, and thus it is not necessary to perform further high-accuracy phase difference AF.

In step #115, if the condition that phase difference AF is not required is not satisfied, it is determined whether or not the AF lock switch associated with the AF lock button 28 is turned on (# 117). In the case where the AF lock switch is not turned on as a result of the determination, phase difference AF is performed below step # 119. That is, if none of the determination results in steps #113, #115, and #117 has passed, high-precision AF is performed by phase difference AF.

To perform the phase difference AF, first, the movable mirror 201 is restored and inserted into the optical path of the photographing optical system 101 (# 119). Thereby, the object beam for phase difference AF is guided to the phase difference AF sensor 243. Next, phase difference AF control is performed (# 121). In this step, the focus defocus direction and focus defocus amount of the photographing optical system 101 are detected by known phase difference AF, and the driving of the optical system driving mechanism 107 is controlled based on the defocus direction and defocus amount, thereby focusing the photographing optical system 101. Details are described later using fig. 9.

When the phase difference AF control is finished, the movable mirror 201 is moved to the raised position, that is, the movable mirror 201 is retracted (# 123). Thus, the subject light flux having passed through the photographing optical system 101 is guided again to the image pickup device 221, and forms an image on the image pickup device 221.

If the determination results in steps #113 and #115 described above both pass "yes", it is not necessary to perform high-precision AF by phase difference AF, and if the determination result in step #117 is that the AF lock switch is on, the photographer has already determined the focus position, and therefore the photographing operation is directly started, and the focus display is turned off before the focus position is not changed by phase difference AF (# 127).

When step #123 or step #127 ends, the photographing operation B of acquiring and recording image data based on the subject image is executed next (# 125). The photographing operation B will be described later with reference to fig. 8. When the photographing operation B is completed, the process returns to step #43 to restart the live view display, and the above-described operation is repeated.

Next, a subroutine of the photographing operation a in step #37 will be described with reference to fig. 7. This photographing operation a is a subroutine executed when the release button 21 is half-pressed in a normal optical viewfinder observation state (i.e., non-live view display). When the subroutine of the photographing operation a is entered, first, the photographing information display is turned off (# 131).

Next, as in step #121, the subroutine of the phase difference AF control is executed (# 133). That is, the defocus direction and the defocus amount are obtained from the output of the phase difference AF sensor 243, and the photographing optical system 101 is focused. Details of this subroutine will be described later with reference to fig. 9.

When the phase difference AF is completed, photometry and exposure amount calculation are performed in the same manner as in step #11, and exposure control values such as a shutter speed and an aperture value are obtained (# 135). Next, it is determined whether or not the shutter button 21 is fully pressed, that is, whether or not the 2R switch is on (# 137). If the determination result is that the 2R switch is not on, it is determined whether the 1R switch is on (# 157). When the 1R switch is not turned on as a result of the determination, the photographing operation a is ended, and the program returns to the original program. On the other hand, if the determination result is that the 1R switch is on, the process returns to step #137, and a state of waiting for the alternate detection of the states of the 1R switch and the 2R switch is set.

When the 2R switch is turned on as a result of the determination in step #137, the process proceeds to a step for performing imaging. First, the movable mirror 201 retreats (moves to the raised position) (# 139). Thereby, the subject light beam of the photographing optical system 101 is guided onto the image pickup element 221 and imaged. Next, the lens CPU111 is instructed to stop down motion (#141), and is instructed to stop down amount (# 143).

Thus, preparation for entering the image capturing operation is made, and the exposure operation is started (# 145). During exposure, movement of the front curtain of the shutter 213 is started, and charge accumulation of the image pickup element 221 is started. When the time corresponding to the shutter speed obtained in step #135 or the shutter speed manually set by the photographer has elapsed, the movement of the rear curtain of the shutter 213 is started, and the charge accumulation of the image pickup element 221 is ended.

When the exposure operation is completed, an instruction to open the diaphragm is output to the lens CPU111 (# 147). Next, an operation of returning the movable mirror 201 to the lowered position is performed (#149), and an image signal is read from the image sensor 221 (# 151). Image processing of the read image signal is performed by the image processing circuit 257 or the like (#153), and the processed image data is recorded in the recording medium 277 (# 155). When the image recording is finished, the original program is returned to.

Next, a subroutine of the photographing operation B in step #125 (fig. 6) will be described with reference to fig. 8. The shooting operation B is a subroutine executed when the release button 21 is fully pressed in the live view display state. When the subroutine of the photographing operation B is entered, the exposure amount is calculated based on the output of the AE circuit 255 (# 161).

Next, as in steps #141 and #143, an instruction to stop down is performed and an instruction to stop down amount is performed (#163 and # 165). Then, as in step #145, an exposure operation is performed (#167), whereby image data of the subject image is acquired based on the output of the image pickup device 221. Thereafter, similarly to steps #147, #151, #153, and #155, the stop is instructed to open (#169), the image signal is read (#171), image processing is performed (#173), and the image signal is recorded in the recording medium 277 (# 175). When the image recording is finished, the original program is returned.

Next, a subroutine of the phase difference AF control in step #121 (fig. 6) and step #133 (fig. 7) will be described with reference to fig. 9. The phase difference AF control uses 2 light beams around the photographing optical system 101 to determine the defocus direction and defocus amount of the photographing optical system 101 by a known phase difference method. It is possible to perform high-precision AF to the same extent as the high-precision AF in contrast AF.

When the phase difference AF control subroutine is entered, focus detection is performed for all points first (# 181). That is, the defocus direction and the defocus amount are detected for all points that can be detected by the phase difference AF sensor 243 and the phase difference AF processing circuit 245. Next, the closest point is selected from all the detected points (# 183). In general, the main subject is the closest subject at the most, and this selection is performed.

Then, it is determined whether or not the focus range is entered based on the defocus amount of the selected closest point (# 185). The criterion of whether or not the defocus amount is within the in-focus range is determined according to whether or not the defocus amount enters the in-focus determination value based on the allowable dispersion circle. When the determination result is that the focus range is within, the program returns to the original program. The allowable circle segment diameter is set according to the imaging resolution of the imaging element 221, in other words, the pixel size of the imaging element 221.

On the other hand, if the determination result is that the focus detection point is not within the in-focus range, the driving direction and the driving amount for driving the photographing optical system 101 by the optical system driving mechanism 107 are calculated based on the defocus direction and the defocus amount at the selected focus detection point (# 187). Then, lens drive control by the optical system drive mechanism 107 is instructed to the lens CPU111 (#189), and the lens drive amount and the drive direction at this time are instructed (# 191).

When the main body CPU251 outputs an instruction of lens driving control to the lens CPU111, it waits for a signal indicating that the lens driving is completed to be input from the lens CPU111 (# 193). When the lens driving is completed, focus detection is performed with respect to the focus detection point selected in step #183 (# 195). When the focus detection is finished, the procedure returns to step #185, and the above steps are repeated before entering the in-focus range.

Next, a subroutine of contrast AF control in step #105 (fig. 6) will be described with reference to fig. 10 and 11. In this contrast AF control, the photographing optical system 101 is driven so that the contrast information in the contrast AF circuit 253 based on the output of the image pickup element 221 is maximized. This contrast AF control can be used in the case where: the movable mirror 201 is located at the backward position (raised position), and the phase difference AF control cannot be performed based on the output of the phase difference AF sensor 243.

Also, in contrast AF control, there are two modes: high-speed contrast AF (1 st contrast AF) in which AF control is performed at a 1 st focusing accuracy at a high speed but with a coarse focusing accuracy, and high-precision contrast AF (2 nd contrast AF) in which AF control is performed at a 2 nd focusing accuracy at a low speed but with a high focusing accuracy.

When the contrast AF control subroutine is entered, the 1 st contrast AF is started, and first, 1 is set to the register DC (# 201). The register DC is a register for determining a driving direction of the lens driving. Next, the lens feed direction is set as the lens driving direction (# 203). Then, the 1 st predetermined value is set as the lens driving amount (# 205). The 1 st predetermined value corresponds to a feed amount LD1 of the focus lens in the photographing optical system 101 in fig. 16A, and is an amount associated with a defocus amount Δ fLCD corresponding to the allowable circle of confusion diameter Φ LCD on the liquid crystal monitor surface in fig. 18.

Then, contrast information is acquired from the contrast AF circuit 253 (# 207). Then, control of lens driving is instructed to the lens CPU111 (#209), and the lens driving amount and the driving direction set in steps #203, #205 are transmitted (# 211). When these signals are transmitted, the lens CPU111 drives the photographing optical system 101 through the optical system driving mechanism 107. When the drive control based on the set drive direction and drive amount is ended, the lens CPU111 sends a signal that the lens drive is completed to the main body CPU 251.

The main body CPU251 waits for reception of a lens drive completion signal (#213), and when received, acquires the latest contrast information from the contrast AF circuit 253 (# 215). Next, it is determined whether the contrast is higher than the previous contrast (# 217). If the contrast is improved this time as a result of the determination, the register DC is incremented by 1(#219), the process returns to step #209, and the above-described steps are repeated.

If the contrast ratio is lower than the previous time as a result of the determination in step #217, it is determined whether the value of the register DC is 1(# 221). If the determination result is that the register DC is 1, the lens driving direction is reversed from the previous one (#223), the process returns to step #209, and the above-described steps are repeated.

That is, when the first lens driving is performed, the lens is driven in the send-out direction once because the direction in which the lens is to be driven is unclear. When the contrast is increased as a result of the driving, the driving direction is positive (close to the in-focus position), and on the other hand, when the contrast is decreased, the driving direction is reversed (away from the in-focus position) because the driving direction is reverse. Therefore, if the register DC is 1, it is determined that the driving is performed for the first time, and the process proceeds to step #223 to invert the driving direction, whereas if the register DC is not 1, it is determined that the contrast has crossed the peak position, and the process proceeds to step # 225.

If the determination result in step #221 is that the register DC is not 1, the lens is driven in the direction to increase the contrast, but since this is a decrease, it is determined that the peak position of the contrast has passed, and the driving direction is set in the opposite direction to the previous one (# 225). Then, the 2 nd predetermined value is set as the lens driving amount (# 227).

The 2 nd predetermined value as the lens driving amount corresponds to half of the sending-out amount LD1 of the focus lens in fig. 16A. Since the peak value of the contrast is exceeded, it is assumed that the peak value is present between the previous time and the present time, and the peak value is set to be half of the 1 st predetermined value. Next, control of lens driving is instructed to the lens CPU111 (#229), and the lens driving amount and the driving direction set in steps #225, #227 are transmitted (# 231).

Upon receiving an instruction for lens drive control, the lens CPU111 starts drive control of the optical system drive mechanism 107, and when the optical system drive mechanism is driven by a drive amount based on the 2 nd predetermined value, transmits a signal indicating completion of lens drive to the main body CPU 251. The main body CPU251 waits for reception of a lens drive completion signal (#233), and when receiving the completion signal, performs the 1 st focus display (# 235). As shown in fig. 15A, this is displayed as a 1 st focus display 311 on the display surface of the liquid crystal monitor 26.

The state in which the 1 st focus display is performed is a horizontal focus state in which the dispersion is not significant when the subject image is confirmed on the liquid crystal monitor 26 even when the photographing is not appropriate, and the focus allowable range is set according to the display resolution of the liquid crystal monitor 26, that is, the allowable circle diameter of confusion based on the display dot size of the liquid crystal monitor 26. Therefore, sufficient focusing accuracy is to be achieved in order to observe the object image on the liquid crystal monitor 26.

Next, it is determined whether or not the display is in the enlarged display (# 237). In step #55, it is determined whether or not the enlargement display is set. When the determination result is not in the enlarged display, it is determined whether or not the 2R switch is on (# 239). If the determination result is that the 2R switch is on, a lens position information request is instructed to the lens CPU111 (# 241). The lens CPU111 acquires lens position information from the optical system position detection mechanism 105, and transmits the lens position information to the main body CPU 251. The main body CPU251 acquires the transmitted lens position information (# 243).

When the focus 1 display is performed in step #235, the display is in the rough focus state by contrast AF control. In this state, in the case of enlargement display, or when the release button 21 is not fully pressed, control is performed by contrast AF control so that an in-focus state with higher accuracy is attained. However, when the release button 21 is fully pressed and the photographing operation is started, the procedure returns to step #107 in fig. 6, and when a predetermined condition is satisfied, the focus control is performed by the phase difference AF control in step #121, and then the photographing operation B in step #125 is performed. The lens position information is acquired in steps #241 and #243 to determine whether or not the condition for unnecessary phase difference AF is satisfied in step # 115.

If it is determined in step #237 that the enlarged display is being performed, or if it is determined in step #239 that the 2R switch is not on, it is determined whether the 1R switch is on (# 245). If the determination result is that the 1R switch is not on, the routine returns to the original routine, whereas if the 1R switch is on, the contrast information is acquired for the 2 nd contrast AF (#251, fig. 11).

Next, the same direction as the previous one is set as the lens driving direction (#253), and the 3 rd predetermined value is set as the driving amount (# 255). The 3 rd predetermined value corresponds to a feed amount LD3 of the focus lens in fig. 16(B), and is an amount correlated with a defocus amount Δ fimg corresponding to the allowable circle diameter Φ img on the imaging plane of the imaging element 211 in fig. 18.

Next, control of lens driving is instructed to the lens CPU111 (#257), and the lens driving amount and the driving direction set in steps #253, #255 are transmitted (# 259). The lens CPU111 controls the optical system driving mechanism 107 to control the driving of the photographing optical system 101. When the drive control ends, since a signal of lens drive completion is sent to the main body CPU251, the main body CPU251 is in a state of waiting for reception of the signal of lens drive completion (# 261).

When the main body CPU251 receives the signal of completion of lens driving, contrast information is then acquired (# 263). Then, it is determined whether the contrast information is higher than the previous contrast information (# 265). If the contrast is improved as a result of the determination, it is determined whether or not the display is enlarged (#283), and it is determined whether or not the 2R switch is turned on (# 285). If the determination result is that the display is enlarged or if the display is not enlarged and the 2R switch is not on, it is determined whether the 1R switch is on (# 287).

If the determination results in steps #283, #285, and #287 are in the enlarged display, or if the 2R switch is off and the 1R switch is on instead of in the enlarged display, the process returns to step #257 and the above steps are repeated as long as the contrast is improved. On the other hand, when the 2R switch is turned on instead of the enlarged display, the process proceeds to step #279, the processes of steps #279 and #281 are performed, and the routine returns to the original routine. In the present embodiment, after the 1 st focus display is performed, in the case of performing the 2 nd contrast AF, if the 2 nd contrast AF is not in the enlarged display, the 2 nd contrast AF is interrupted when the 2R switch is turned on, but on the other hand, in the case of being in the enlarged display, the 2 nd contrast AF is not interrupted even if the 2R switch is turned on because the turning on of the 2R switch is not detected.

If the contrast is decreased as a result of the determination in step #265, the direction opposite to the previous one is set as the driving direction (#267), and the 4 th predetermined value is set as the driving amount (# 269). The 4 th predetermined value as the lens driving amount corresponds to half of the sending-out amount LD3 of the focus lens in fig. 16B. Since the peak value of the contrast is exceeded, it is assumed that the peak position is present between the previous time and the present time, and the peak position is set to be half the 3 rd predetermined value.

Next, control of lens driving is instructed to the lens CPU111 (#271), and the lens driving amount and driving direction set in steps #267, #269 are transmitted (# 273). Upon receiving an instruction for lens drive control or the like, the lens CPU111 performs drive control by the optical system drive mechanism 107, and when the drive control is completed, transmits a signal indicating the completion of the drive to the main body CPU 251. The main body CPU251 waits for reception of the lens drive completion signal (#275), and when the drive completion signal is received, the 2 nd focus display is performed (# 277).

As shown in fig. 15B, this display is performed on the display surface of the liquid crystal monitor 26, together with the 1 st focus display 311, as the 2 nd focus display 312. The state in which the 2 nd focus display 312 is displayed is a high-precision focus state to the same extent as the allowable circle diameter of the pixel of the image pickup element 221, and is to the same extent as the focus precision in the phase difference AF. When the focus 2 display 312 is performed, a lens position information request is subsequently instructed similarly to step #241 (#279), and lens information is acquired similarly to step #243 (#281) and returned to the original program.

In the present embodiment, when the peak position of the contrast is passed, the driving amount is halved and the driving is performed in the reverse direction (#225, #227, #267, #269), but the present invention is not limited to this, and the peak position of the contrast can be moved by interpolation operation such as 3-point interpolation, for example.

Next, the focusing accuracy of contrast AF in the present embodiment will be described with reference to fig. 16 to 18. As shown in fig. 17A, the pixels on the imaging surface of the imaging element 221 are 3648 pixels in the horizontal direction and 2738 pixels in the vertical direction. On the other hand, assuming that the liquid crystal monitor surface of the liquid crystal monitor 26 is configured by 640 pixels in the horizontal direction and 320 pixels in the vertical direction as shown in fig. 17B, the allowable circle of confusion diameter is about 1/7 and about 1/4 in comparison with the image pickup device 221, and therefore the allowable circle of confusion diameter Φ LCD of the liquid crystal monitor 26 is:

φLCD＝(3648/640)*φimg/α

≒4*φimg

the allowable defocus amount Δ fpcd for the liquid crystal monitor corresponding to the allowable circle diameter Φ LCD of the liquid crystal monitor 26 is:

ΔfLCD＝φLCD /F

here, F: aperture value of lens (FNo.)

F ═ D/F (D: aperture, F: focal length)

Therefore, the focusing accuracy in the 1 st focusing display (#235) is the 1 st predetermined value of the driving amount, and as shown in fig. 16A, the focusing accuracy around the permissible circle-of-confusion diameter Φ LCD of the liquid crystal monitor 26 can be obtained by using β × Δ fLCD as the 1 st predetermined value. Here, β ≈ 5 to 15(β is an empirical value).

On the other hand, as shown in fig. 17A, the imaging surface (light receiving surface) of the image pickup element 221 is composed of 3648 pixels in the horizontal direction and 2838 pixels in the vertical direction. The allowable circle diameter Φ img of the image pickup element 221 is:

φimg＝α*X

here, α: LPF coefficient (1.5 ~ 2.)

X: size of pixel

The LPF coefficient is a coefficient affected by the infrared cut filter/low pass filter 217, and thus the allowable circle diameter Φ img of the image pickup element 221 is obtained by multiplying the coefficient in consideration of the low pass filter by the pixel size of the image pickup element.

Then, the allowable defocus amount Δ fimg for imaging corresponding to the allowable circle diameter Φ img of the imaging element 221 is:

Δfimg＝φimg/F

here, F: aperture value of lens (FNo.)

F ═ D/F (D: aperture, F: focal length)

Therefore, the focusing accuracy in the 2 nd focus display (#277) is set to the driving amount as the 2 nd predetermined value, and as shown in fig. 16B, the focusing accuracy around the allowable circle diameter Φ img of the image sensor 221 can be obtained as long as γ × Δ fimg is used as the 2 nd predetermined value. Here, γ ≈ 3(γ is an empirical value). The numbers of pixels and the like described above are examples, and the allowable circle diameter, defocus amount, and drive amount corresponding to the design values of the imaging device may be determined. The focusing tolerance range in the phase difference AF is also determined by Δ fimg.

Next, the operation of the lens CPU111 of the interchangeable lens 100 will be described with reference to fig. 12. First, it is determined whether or not an instruction for a lens information request is given by the main body CPU251 (# 301). If the determination result is that the request instruction is made, the lens information is transmitted (# 311). The lens information here is lens specific information such as an aperture opening value, a minimum aperture value, color balance information of the lens, aberration information, and AF information, and is stored in the lens CPU111 or an electrically rewritable memory such as an EEPROM (not shown).

If the determination result in step #301 is an instruction that is not a lens information request, it is determined whether the lens position information request is made (# 303). If the determination result is that the position information request is made, the lens position information is transmitted to the main body CPU251 (# 313). Since the lens position information is detected by the optical system position detection mechanism 105, the information is transmitted.

If the determination result in step #303 is that the instruction is not a position information request, it is determined whether the instruction is a diaphragm reduction instruction (# 305). If the determination result is that the instruction to stop down is given, the stop-down amount transmitted from the main CPU251 is received next (# 315). When the amount of reduction of the diaphragm is received, the diaphragm driving mechanism 109 controls the diaphragm 103 to reduce the diaphragm (# 317).

If the determination result in step #305 is not the diaphragm stop-down instruction, it is determined whether or not the instruction is a diaphragm open instruction (# 307). If the determination result is that the instruction to open the diaphragm is issued, the diaphragm driving mechanism 109 controls the diaphragm 103 to open the diaphragm (# 317).

If the determination result in step #307 is not the stop opening instruction, it is determined whether or not the instruction is an instruction for lens drive control (# 309). If the determination result is an instruction for lens driving control, the transmitted lens driving amount and driving direction are received next (# 321). Upon receiving the lens driving amount and the driving direction, the lens CPU111 controls the optical system driving mechanism 107 to perform driving control of the photographing optical system 101 (# 323). Then, when the predetermined driving amount is driven, a signal of completion of lens driving is sent to the main body CPU251 (# 325).

As described above, in the present embodiment, after contrast AF is performed in step #105, phase difference AF is performed in step # 121. In contrast AF, at least high-speed focus adjustment with coarse focusing accuracy is performed, and in step #121, high-accuracy phase difference AF is performed. Although the focusing accuracy of the contrast AF is coarse accuracy (1 st focusing accuracy), it takes less time from the focusing state to the completion of the high-accuracy focus adjustment because it is in a rough focusing state, and therefore, it is possible to perform the high-accuracy focus adjustment with a small delay time.

In the determination of step #113 in the present embodiment, when focus display 2 is performed, that is, when focus is performed in high-precision contrast AF, phase difference AF in step #121 is omitted. That is, the present embodiment includes: a 1 st focus adjustment mode in which focus adjustment is performed by a combination of high-speed contrast AF and phase difference AF, and a 2 nd focus adjustment mode in which focus adjustment is performed by high-precision contrast AF after the high-speed contrast AF. Therefore, in the 2 nd focus adjustment mode, the phase difference AF can be omitted, and the delay time can be shortened in accordance with the time required for the phase difference AF. In addition, in the high-precision contrast AF, the focus adjustment can be performed with a high degree of precision as in the phase difference AF, and sufficient focusing precision can be ensured.

In step #115 of the present embodiment, a condition that phase difference AF is unnecessary is determined, and when the unnecessary condition is satisfied, phase difference AF in step #121 is omitted. Therefore, the delay time can be shortened in accordance with the time required for the phase difference AF, and the focus adjustment can be performed with high accuracy. In addition, as the condition that the phase difference AF is not required, in the present embodiment, the determination is made under 3 conditions, but not limited to this, other conditions may be added, and any one of the conditions may be omitted. In any case, even if the phase difference AF with high accuracy is not performed, the phase difference AF can be omitted as long as sufficient focusing accuracy can be obtained.

In step #117 of the present embodiment, it is determined whether or not AF lock is performed, and if AF lock is performed, phase difference AF in step #121 is omitted. Therefore, the delay time can be shortened in accordance with the time required for the phase difference AF. In particular, in the case of AF lock, in many cases, the photographer has already determined the focus position and wants to perform photographing quickly, and at least the 1 st focus display is performed, and it is possible to secure approximate focus accuracy. In the present embodiment, the phase difference AF is omitted when the AF lock button 28 is operated, but the phase difference AF is not limited to the AF lock button 28, and may be omitted when another operation member is operated.

In the present embodiment, when the enlarged display is performed, the phase difference AF is omitted. In the enlarged display before the 2 nd focus display is performed, the determination of the state of the 2R switch is prohibited in steps #237, #239, and #283, # 285. Therefore, when the zoom-in display is performed, the release button 21 is fully pressed, and when the photographing operation is performed, the phase difference AF with high accuracy is not required. Therefore, the phase difference AF in step #121 can be omitted, the delay time can be shortened in accordance with the time required for the phase difference AF, and sufficient focusing accuracy can be ensured.

As described above, in the embodiment of the present invention, an imaging apparatus includes: an image pickup element 221 that receives an object light beam incident via the photographing optical system 101 with an image pickup surface, photoelectrically converts an object image formed on the image pickup surface, and outputs object image data; a liquid crystal monitor 26 that performs live view display using the subject image data acquired by the image pickup device 221; contrast AF means (contrast AF circuit 253 or the like, #105 contrast AF control) for obtaining contrast information of the subject image from the subject image data while performing the live view display operation, and for bringing the photographing optical system 101 into a predetermined focus allowable range based on the contrast information; and a phase difference AF unit (phase difference AF sensor 243 and the like, #121 phase difference AF control) that causes the movable mirror 201 to enter the optical path of the photographing optical system 101, receives the object light beam reflected by the movable mirror 201, detects the defocus amount of the photographing optical system 101 in a phase difference manner, and guides the photographing optical system 101 into a focus allowable range narrower than the focus allowable range of the contrast AF unit based on the detection result, wherein if a half-press operation of the release button 21 is performed during execution of the live view display operation (#53 → "yes"), the focus adjustment operation is performed by the contrast AF unit (#105), and thereafter, if a full-press operation of the release button 21 is performed (#107), the focus adjustment operation is performed by the phase difference AF unit (# 121).

Therefore, in the present embodiment, when shooting is performed from the live view display state, a coarse focusing operation is performed by the contrast AF unit on the monitor to the extent that the dispersion cannot be confirmed during the live view display, and a high-precision focus adjustment operation is performed by the phase difference AF unit to the extent that the shooting can be performed when the shooting operation is started.

In an embodiment of the present invention, an imaging apparatus includes: a 1 st contrast AF unit (contrast AF circuit 253, #201 to #253 contrast AF control) that obtains contrast information of an object image from object image data acquired by the image pickup element 221 and introduces the photographing optical system 101 into a 1 st focus allowable range based on the contrast information; a 2 nd contrast AF unit (contrast AF circuit 253, #201 to #277 contrast AF control) that guides the photographing optical system 101 into a 2 nd focus allowable range narrower than the 1 st focus allowable range according to the contrast information; and a phase difference AF unit (phase difference distance measuring sensor 243, #121 phase difference AF control) that causes the movable mirror 201 to enter the optical path of the photographing optical system 101, receives the subject light beam reflected by the movable mirror 201, detects the defocus amount of the photographing optical system in a phase difference manner, and guides the photographing optical system 101 to a focus allowable range narrower than that of the 1 st contrast AF unit based on the detection result, wherein the photographing apparatus selects: a 1 st focus adjustment mode in which focus adjustment of the photographing optical system 101 is performed by a combination of the 1 st contrast AF unit and the phase difference AF unit, and a 2 nd focus adjustment mode in which focus adjustment of the photographing optical system 101 is performed only with the 2 nd contrast AF unit.

Therefore, in the present embodiment, since the 1 st focus adjustment mode using the combination of the 1 st contrast AF unit and the phase difference AF unit and the 2 nd focus adjustment mode using only the 2 nd contrast AF unit are selected according to the situation, it is possible to perform focus adjustment with less delay and high accuracy.

In the embodiment of the present invention, the imaging apparatus includes an enlargement operation unit (enlargement buttons 34, #55 to #75) for performing enlarged live view display for cutting out a partial range of the acquired image data and performing live view display during execution of the live view display operation, and the imaging apparatus performs control such that: if the half-press operation of the release button 21 is performed during the execution of the live view display operation (#53 → "yes"), the focus adjustment operation is performed by the contrast AF unit (#105), then if the full-press operation of the release button 21 is performed (#107), the focus adjustment operation is performed by the phase difference AF unit (#121), if the half-press operation of the release button 21 is performed during the enlarged live view display (#53 → "yes"), a subroutine of the contrast AF control is executed (#105), after the 1 st contrast AF control for introducing the photographing lens into the 1 st focus allowable range is performed, the 2 nd contrast AF control for introducing the photographing lens into the 2 nd focus allowable range narrower than the 1 st focus allowable range is performed, and if the full-press operation of the release button 21 is performed in the state where the 2 nd focus display is performed (#107), the focus adjustment action is performed without using the phase difference AF unit (#113, # 127).

Therefore, in the present embodiment, when the enlarged live view display is performed, the focus adjustment operation is not performed by the phase difference AF unit after the full-press operation of the release button 21, and therefore, it is possible to perform the focus adjustment with a small delay time and high accuracy.

Next, embodiment 2 of the present invention will be described with reference to fig. 19 to 23. In embodiment 1, when the zoom-in display is performed during the live view display, the 2 nd contrast AF continues to perform the high-precision focus adjustment operation even when the 1 st contrast AF is in the in-focus state. In embodiment 2, the phase difference AF enables multipoint distance measurement, and when the zoom-in display is performed during live view display, the phase difference AF performs highly accurate focus adjustment for the portion subjected to the zoom-in display as the release button 21 is fully pressed.

Embodiment 2 is the same as embodiment 1 in the external configuration and circuit shown in fig. 1 and 2 except that the flowcharts shown in fig. 6, 9, 10, and 11 of embodiment 1 are replaced with fig. 19 to 22. Therefore, the differences from embodiment 1 will be mainly described, and steps for performing the same processing will be denoted by the same reference numerals, and detailed description thereof will be omitted.

The flowchart shown in fig. 19 shows the live view display operation, and when the release button 21 is half-pressed in step #53 of the flowchart shown in fig. 4 in embodiment 1, that is, when the 1R switch is turned on, the process jumps to step # 101. In step #101, AE information is read as in embodiment 1.

Next, it is determined whether or not the focus 2 display is in progress (# 102). When the photographing optical system 101 is brought into the 2 nd focus state by the high-precision contrast AF, the 2 nd focus display is performed (#277 in fig. 22). When the photographing optical system 101 is driven again by contrast AF in step #105 after the focus 2 state is reached, the operation feeling is poor, and thus step #105 is skipped when the focus 2 state is reached.

If the determination result in step #102 is that no focus display is being performed in 2 nd, it is determined whether or not the mode is the phase difference AF only mode (#103) as in #103 of embodiment 1.

If the determination result in step #103 is the phase difference AF only mode, or if the determination result in step #102 is in the 2 nd in-focus display, the process proceeds to step #107, whereas if the determination result in step #103 is not the phase difference AF only mode, contrast AF control is performed (# 105). In this contrast AF control, control is performed such that the photographing optical system 101 is in focus, based on contrast information from the contrast AF circuit 253. Details of this contrast AF control will be described later using fig. 21 and 22.

Since step #107 and thereafter are the same as those in the flowchart of fig. 6 of embodiment 1, steps for performing the same processing are denoted by the same reference numerals, and detailed description thereof is omitted.

Next, a subroutine of the phase difference AF control in step #121 (fig. 19) and step #133 (fig. 7) will be described with reference to fig. 20. In the phase difference AF control, the peripheral 2 light flux of the photographing optical system 101 is used to determine the defocus direction and defocus amount of the photographing optical system 101 by a known phase difference method. High-precision AF of the same degree as that in contrast AF can be performed.

When the subroutine of the phase difference AF control is entered, first, it is determined whether or not the display is being enlarged (# 180). That is, in the live view display, the zoom-in display mode is entered in step #55 (fig. 4), and in this state, the release button 21 is fully pressed (#107, fig. 19), and it is determined whether or not the phase difference AF control subroutine is entered. If the determination result is that the display is not in the enlarged display, focus detection is performed for all the dots (# 181).

In this step #181, the defocus direction and the defocus amount are detected for all points detectable by the phase difference AF sensor 243 and the phase difference AF processing circuit 245. On the other hand, when the determination result is that the display is being enlarged, the defocus direction and the defocus amount are detected by the phase difference method for the point in the enlargement range. The distance measurable points in the phase difference AF method are positions (focus detection points 322) where "+" marks are given on the imaging screen 321 shown in fig. 23A, and are all 11 points in this example.

In step #181, focus detection is performed for all of these focus detection points 322. In the enlargement display mode, the live view display is displayed in enlargement in the enlargement area 323 indicated by the broken line in fig. 23B, and the enlargement area 323 indicated by the broken line is moved by operating the cross button 30, for example, as shown in fig. 23C. The focus detection point 322 included in the enlargement area 323 also changes as the enlargement area 323 moves. In step #182, when the release button 21 is fully pressed, focus detection (defocus direction and defocus amount) is performed on the focus detection point 322 included in the enlarged display area by the phase difference AF method.

After the processing in step #181 or step #182 is performed, the closest point is selected (#183), and the processing after step #183 is the same as the flowchart in fig. 9 of embodiment 1, and therefore the same reference numerals are assigned to the same processing, and detailed description thereof is omitted.

Next, a subroutine of contrast AF control in step #105 (fig. 19) will be described with reference to fig. 21 and 22. The contrast AF control is performed to drive the photographing optical system 101 so that the contrast information in the contrast AF circuit 253 based on the output of the image pickup element 221 is maximized, as in embodiment 1. As in embodiment 1, the contrast AF control has two modes: high-speed contrast AF (1 st contrast AF) in which AF control is performed at a 1 st focusing accuracy at a high speed but with a coarse focusing accuracy, and high-precision contrast AF (2 nd contrast AF) in which AF control is performed at a 2 nd focusing accuracy at a low speed but with a high focusing accuracy.

When the subroutine of contrast AF control is entered, the register DC is set and the driving direction and the driving amount are set as in embodiment 1(#201 to # 205). Next, contrast information is acquired from the contrast AF circuit 253 (# 207). In this case, when performing non-enlarged live view display, contrast information of image data corresponding to the entire shooting screen is acquired. When the 1R switch is turned on during the enlarged display, the contrast information acquired here is based on the image data cut out for the enlarged display. The same applies to the contrast information acquired in step #215 described later and the like. When the contrast information is acquired, step #209 is executed or less, but before step #235, the same as in embodiment 1 is performed, and thus detailed description is omitted.

When the focus 1 display is performed in step #235, it is next determined whether the release button 21 is fully pressed, that is, whether the 2R switch is on. In embodiment 1, before determining the 2R switch, it is determined whether or not the display is in the enlarged display (#237 in fig. 10), and if the display is in the enlarged display, the 2 nd contrast AF is executed. In contrast, in embodiment 2, when the zoom-in display is performed, the focus adjustment with high accuracy is performed for the object corresponding to the zoom-in display portion by the multipoint phase difference AF, and thus the determination as to whether or not the zoom-in display is performed is omitted.

If the determination result in step #245 is that the 1R switch is on, the process proceeds to step #251 shown in fig. 22. The flowchart shown in fig. 22 is the same as the flowchart shown in fig. 11 in embodiment 1 except that step #283 is omitted. That is, in embodiment 1, in the enlarged display, the state determination of the 2R switch in step #285 is not permitted until the 2 nd in-focus state is reached by the 2 nd contrast AF with high accuracy. In contrast, in embodiment 2, when the 2R switch is turned on while the zoom-in display is in progress, the operation shifts to the release operation, and in the release operation, the focus adjustment with high accuracy is performed by the multipoint phase difference AF. Therefore, the determination of whether or not the enlarged display is performed in step #283 in embodiment 1 is omitted.

As described above, in embodiment 2 of the present invention, when the zoom-in display is performed in the live view display mode (#55 → #75 in fig. 4), the full-press operation is performed on the release button (#53 yes "→ #107 yes"), and when the image capturing operation is shifted, the phase difference AF method is used to detect the defocus amount at the focus detection point (#182 in fig. 20) included in the zoom-in region. Therefore, it is possible to perform automatic focus adjustment for an area in which the photographer performs enlarged display, that is, an object that the photographer wants to focus on. Further, since the phase difference AF is not performed for all the focus detection points, the distance measurement time can be shortened, and high-precision focusing accuracy can be ensured by the phase difference AF.

In the determination of step #113 in the present embodiment, when the focus 2 display is performed, that is, when focusing is performed with high-precision contrast AF, the phase difference AF in step #121 is omitted. That is, the present embodiment includes: the 1 st focus adjustment mode in which focus adjustment is performed by a combination of high-speed contrast AF and phase difference AF, and the 2 nd focus adjustment mode in which focus adjustment is performed by high-precision contrast AF after the high-speed contrast AF, and by omitting the phase difference AF, the delay time can be shortened in response to the time required for the phase difference AF. In addition, in the high-precision contrast AF, the focus adjustment can be performed with a high degree of precision as in the phase difference AF, and sufficient focusing precision can be ensured. Further, since the half-press of the release button 21 and the automatic focus adjustment using the contrast AF are performed during the enlarged display, sufficient focusing accuracy is obtained in the case where the 2 nd focus display is performed, and therefore the phase difference AF is omitted, and the time required for the automatic focus adjustment is shortened.

As described above, in the embodiment of the present invention, an imaging apparatus includes: a contrast AF unit (contrast AF circuit 253 or the like, #105 contrast AF control) that obtains contrast information of the subject image from the subject image data and introduces the photographing optical system 101 into a predetermined allowable focus range (focus range 1) based on the contrast information; a phase difference AF unit (phase difference AF sensor 243, phase difference AF processing circuit 245, etc.) including a phase difference AF sensor 243 that detects the defocus amount of the photographing optical system 101 by a phase difference method for a plurality of points within a photographing screen, and that guides the photographing optical system 101 to a focus allowable range narrower than the focus allowable range of the contrast AF unit based on any of a plurality of defocus amount information detected by the phase difference AF sensor 243; and a control unit (main body CPU 251) that performs control such that, when the half-press operation of the release button 21 is performed during execution of the live view display operation (#53 yes), the focus adjustment operation is performed by the contrast AF unit (#105), and thereafter, when the full-press operation of the release button 21 is performed (#107), the focus adjustment operation is performed by the phase difference AF unit (# 121). The liquid crystal monitor 26 can display a part of the photographing screen in an enlarged manner (enlarged display mode, see fig. 13), and the phase difference AF unit detects the defocus amount with respect to the focus detection points (fig. 23(B) and (C)) included in the enlarged area in a state where enlarged live view display is performed (# 182).

In embodiment 2 of the present invention, an imaging apparatus includes: enlargement display means (preprocessing circuits 225, #55 to #75) for cutting out a part of the subject image data and enlarging and displaying it on the liquid crystal monitor 26 in accordance with an operation of the enlargement button 34; and a phase difference AF unit (phase difference AF sensor 243, phase difference AF processing circuit 245, etc.) including a phase difference AF sensor 243 that detects the defocus amount of the photographing optical system 101 by a phase difference method for a plurality of points within the photographing screen, and that introduces the photographing optical system 101 into the focus allowable range based on any of a plurality of defocus amount information detected by the sensor 243. When the release button 21 is operated, the phase difference AF means detects a defocus amount at a focus detection point (see fig. 23B and 23C) existing within a range enlarged and displayed by the enlargement display means (#182), and the focus adjustment operation of the photographing lens is performed based on the detection result (#185 to # 195).

As described above, according to embodiment 2 of the present invention, the phase difference AF method is used to detect the defocus amount at the focus detection point included in the enlarged area, and the photographer can focus on the object desired by the photographer. Further, the distance measurement time can be shortened as compared with the case where the distance measurement is performed for all the focus detection points.

In addition, in embodiment 2 of the present invention, in the subroutine of the phase difference AF control, the closest point (#183) is selected among the focus detection points, but not limited to this, an intermediate value or the like of a plurality of focus detection results may be selected, and the plurality of focus detection results may be appropriately processed by evaluation calculation.

Next, embodiment 3 of the present invention will be described with reference to fig. 24 to 29. In embodiments 1 and 2 of the present invention, a macro lens or the like is attached, and when the depth of a scene to be photographed becomes shallow, a method of changing focus adjustment is not separately performed. In embodiment 3, in this case, focus adjustment is performed by contrast AF with high accuracy.

Embodiment 3 is the same as embodiment 1 in the external configuration and circuit shown in fig. 1 and 2, except that the flowcharts shown in fig. 3 to 6, 10 and 11 of embodiment 1 are replaced with those shown in fig. 24 to 29. Therefore, differences from embodiment 1 will be mainly described, and steps for performing the same processing will be denoted by the same reference numerals. In embodiment 3, the enlarged display mode is omitted for simplicity of explanation.

The flowchart shown in fig. 24 shows the power-on reset operation, and performs substantially the same processing as the power-on reset operation shown in fig. 4 in embodiment 1. However, if the 1R switch is not turned on as a result of the determination in step #21, the light is turned off for focus display (# 22). As described later, when the in-focus state is achieved by the contrast AF and the object is in focus, as shown in fig. 14A and 14B, the 1 st focus display 311 and the 2 nd focus display 312 (#235 in fig. 10 and #277 in fig. 11) are displayed, and when the in-focus display is performed, the focus display is turned off. Although the lighting off in the focus display is performed in step #85 in embodiments 1 and 2, it is needless to say that step #22 may be added in addition to this step as in embodiment 3, and the lighting off in the focus display may be performed also in this step.

Next, a subroutine of the live view display operation in step #31 will be described with reference to fig. 25 to 27. The live view display operation is different only in the following points: in embodiment 1, the enlarged display mode is omitted, and the determination as to whether or not the focus is in the 2 nd focus is added in step #102 as in embodiment 2, and therefore, a difference will be mainly described.

When the determination result in step #53 is that the 1R switch is off, the routine proceeds to the subroutine of the live view display operation, and the focus display is turned off in the same manner as in step #22 (# 54). In embodiment 1, the processing for the enlarged display mode is performed in steps #55 to #77, but in the present embodiment, the enlarged display mode is omitted.

When the 1R switch is turned on as a result of the determination in step #53, the AE information is read in step #101, and then it is determined whether or not the 2 nd focus display is in progress (#102 in fig. 27) as in embodiment 2. As described later, when the photographing optical system 101 is brought into focus by the 2 nd contrast AF control with high precision, the 2 nd focus display is performed (#277 in fig. 29). When the photographing optical system 101 is driven again by contrast AF in step #105 after the high-precision in-focus state is achieved, the operation feeling is poor, and thus step #105 is skipped when the in-focus state is achieved.

Next, a subroutine of contrast AF control in step #105 (see fig. 27) will be described with reference to fig. 28 and 29. When the subroutine of contrast AF control is entered, contrast AF is performed with the 1 st focusing accuracy from step #201, and the 1 st focusing display is performed when the 1 st focusing state is reached (#235), however, these steps are the same as in the case of embodiment 1, and therefore, the same reference numerals are attached to the steps for performing the same processing as in fig. 10, and detailed description is omitted.

When the 1 st focus display is performed, 0 is set to the close range flag (# 1236). The short-distance flag is set to 1 when the focal position of the photographing optical system 101 is on the short-distance side of the predetermined photographing magnification or the predetermined distance. Then, the lens CPU111 is instructed to request lens information (#1237), and the type of replacement lens such as a macro lens, the maximum photographing magnification, and other lens information are acquired (# 1238).

Then, a request for lens position information is made to the lens CPU11 (#1239), lens position information, that is, focal position information of the photographing optical system 101 is acquired (#1240), and photographing magnification calculation is performed (# 1241). The photographing magnification is calculated from the lens position information and the lens information.

Then, it is determined whether or not the attached interchangeable lens 100 is a macro lens based on the acquired lens information (# 1242). If the interchangeable lens 100 is not a macro lens as a result of the determination, it is determined whether or not the shooting mode read in step #9 (fig. 24) is a macro mode (# 1243). The macro mode is an imaging mode suitable for imaging a subject at a short distance.

If the determination result in step #1242 is the macro lens or if the determination result in step #1243 is the macro mode, it is determined whether or not the photographing magnification is 1/4 or more of the maximum photographing magnification (# 1245). If the determination result in step #1245 is yes, 1 is set to the short-distance flag (# 1246).

If the determination result in step #1245 is no, or if the determination result in step #1243 is not in the macro mode, it is determined whether or not the 2R switch is on (# 1247). When the 2R switch is turned on as a result of the determination, the program returns to the original program to shift to the shooting state. On the other hand, if the 2R switch is not turned on, or if 1 is set to the short range flag in step #1246, it is determined whether or not the 1R switch is turned on (# 1248). If the determination result is that the 1R switch is off, the routine returns to the original routine, and if the 1R switch is on, the routine proceeds to step #1251 (fig. 29) or less, and high-precision 2 nd contrast AF is performed.

In step #1246, the short-distance flag is set to 1 because the photographing magnification is not less than 1/4 of the maximum photographing magnification in a state where the macro lens is attached or the macro mode is set, and the photographer wants to focus on the object at the short-distance side. When the focal position is on the close range side, the depth of the scene to be photographed is shallow, and therefore it is desirable not to shift to the photographing operation until the 2 nd contrast AF control with high accuracy is completed. Therefore, when 1 is set to the short range flag, it is not determined whether or not the 2R switch is on in step # 1247.

When the 1R switch is turned on as a result of the determination in step #1248, contrast information is acquired (#251 in fig. 29). In steps #251 to #281, high-precision 2 nd contrast AF control is performed, but since these steps are the same as those in embodiment 1, the same reference numerals are given to the steps for performing the same processing as in fig. 11, and detailed description thereof is omitted.

In step #265, it is determined whether or not the contrast information is higher than the previous contrast, and if the result of the determination is that the contrast is higher, it is determined whether or not the short-distance flag is 1(#1283), and it is determined whether or not the 2R switch is on (# 285). If the short range flag is 1 or if the short range flag is not 1 and the 2R switch is not on as a result of these determinations, it is determined whether the 1R switch is on (# 287).

If the short range flag is 1 or the short range flag is not 1 and the 2R switch is off and the 1R switch is on as a result of determination in steps #1283, #285, #287, the process returns to step #257 and repeats as long as the contrast is improved. On the other hand, when the short range flag is not 1 and the 2R switch is on, the routine jumps to step #279, and after the processing of steps #279 and #281 is performed, the routine returns to the original routine. In the present embodiment, when the 2 nd contrast AF is performed after the 1 st focus display is performed, the 2 nd contrast AF is interrupted when the close range flag is not 1 and the 2R switch is on; on the other hand, when the close range flag is 1, since the state of the 2R switch is not detected, the 2 nd contrast AF is not interrupted even if the 2R switch is turned on.

The process proceeds to step #257 or step #279 in accordance with the determination result in step #285 or step #287, and the subsequent operation is the same as that in embodiment 1, and therefore the steps for performing the same processing as that in fig. 11 are given the same reference numerals, and detailed description thereof is omitted.

As described above, in embodiment 3 of the present invention, when the photographing magnification at the 1 st focusing of the 1 st contrast AF control is greater than 1/4 of the maximum magnification of the attached interchangeable lens 100 (yes in #1245), that is, when the subject is in a close range, in other words, when focusing is performed in an area where the subject scene depth is shallow, the 2 nd contrast AF control is executed to a high precision. That is, when the 1 st contrast AF control is performed, the close range flag is set when the subject is on the close range side (a region where the subject scene depth is shallow), and when the 2 nd contrast AF control is performed, even if the release button 21 is fully pressed and the 2R is turned on, the shooting operation is not shifted to (when the close range flag is set in #1283, the 2R switch is not determined in #285) before the high-precision in-focus state is reached (# 277). As a result, in the case where the close range flag is set to 1, the 2 nd contrast AF is selected.

When the subject is located on the near side (when the subject is located in an area where the depth of the subject scene is shallow), according to the present embodiment, since the contrast AF control is performed with high accuracy, it is possible to photograph in focus. In the present embodiment, in step #1245, it is determined whether or not the photographing magnification is larger than 1/4 of the maximum photographing magnification, but the determination value may be changed as appropriate in consideration of the characteristics of the photographing lens and the like. In the present embodiment, the determination in step #245 is made based on the photographing magnification, but the determination may be made based on the object distance. Further, since the depth of the scene to be photographed also changes depending on the focal distance of the interchangeable lens 100, the aperture value at the time of photographing, and the like, it is needless to say that the determination may be performed in consideration of these characteristic values.

In embodiment 3 of the present invention, it is determined whether or not the shooting mode is the macro mode, but the present invention is not limited to this, and a mode in which shooting is performed in a region where the depth of the subject scene is shallow, such as the portrait mode, may be the object of determination. Also, in the present embodiment, whether or not it is a macro lens is determined, but it is needless to say that the determination may be made in accordance with the closest side object distance of the interchangeable lens 100.

In embodiment 3 of the present invention, an imaging apparatus includes: a 1 st contrast AF unit (contrast AF circuit 253, etc., #201 to #235) that obtains contrast information of the subject image from the image data and introduces the photographing optical system 101 into a 1 st focus allowable range based on the contrast information; a 2 nd contrast AF unit (contrast AF circuit 253, etc., #251 to #287, and #1283) that guides the photographing optical system 101 into a 2 nd focus allowable range narrower than the 1 st focus allowable range based on the contrast information; determination means (#236 to #246) that determine whether or not the photographing optical system 101 is focused in a region where the depth of the scene to be photographed is shallow; and a control unit (main body CPU251, branch #1283) that, when the half-press operation of the release button 21 is performed during execution of the live view display operation, selects whether to introduce the photographing optical system 101 into the 1 st focus allowable range by the 1 st contrast AF unit or to introduce the photographing optical system 101 into the 2 nd focus allowable range by the 2 nd contrast AF unit, based on a determination result of the determination unit.

In embodiment 3 of the present invention, an imaging apparatus includes: a 1 st contrast AF unit (contrast AF circuit 253, etc., #201 to #235) that obtains contrast information of the subject image from the image data and introduces the photographing optical system 101 into a 1 st focus allowable range based on the contrast information; a 2 nd contrast AF unit (contrast AF circuit 253, etc., #251 to #287) that guides the photographing optical system 101 into a 2 nd focus allowable range narrower than the 1 st focus allowable range based on the contrast information; determination means (#236 to #246) for determining the type or the imaging mode of the imaging optical system 101; and a control unit (main body CPU251, branch #1283) that selects either one of the 1 st contrast AF unit and the 2 nd contrast AF unit according to a determination result of the determination unit in a case where a half-press operation of the release button 21 is performed in execution of the live view display action.

As described above, according to embodiment 3 of the present invention, it is determined whether or not imaging is performed in an area where the depth of the scene to be imaged is shallow (near side), and the control of the contrast AF control means is changed according to the determination result, so that highly accurate focus adjustment with less delay time can be performed.

In embodiment 3 of the present invention, it is determined whether or not to perform imaging on the near distance side (region where the depth of the subject scene is shallow), and the focus adjustment operation using the phase difference AF is not performed when the release button is fully pressed based on the determination result, so that it is possible to perform highly accurate focus adjustment with little delay.

In addition, in embodiments 1 to 3 of the present invention, the object light beam is switched to the finder optical system and the image pickup element as the movable mirror 201 is moved up and down, but not limited to this, a half mirror may be arranged to distribute the object light beam. Also, the focusing accuracy by the phase difference AF is the same as that in the 2 nd focus display by the high-accuracy contrast AF, but is not limited thereto, and any focusing accuracy may be high. However, the focusing accuracy by the phase difference AF is adopted to be higher than that at the time of the 1 st focus display in the high-speed contrast AF.

Further, although the example of applying the present invention to a single-lens reflex camera has been described as the digital camera in embodiments 1 to 3 of the present invention, the present invention is applicable to an electronic imaging apparatus such as a digital camera capable of performing live view display and performing focus adjustment by switching between contrast AF and phase difference AF.

Although the present invention has been described above using the embodiments 1 to 3, the present invention is not limited to the above embodiments, and the constituent elements may be modified and embodied in the implementation stage within the scope not departing from the gist of the present invention. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some of all the components described in the embodiments may be deleted.

Claims (25)

1. A photographing apparatus includes:

an image pickup device that receives an object light beam incident via a photographing lens on an image pickup surface, photoelectrically converts an object image formed on the image pickup surface, and outputs object image data;

a display device that performs a live view display operation using the subject image data acquired by the imaging device;

a 1 st contrast AF device that obtains contrast information of the subject image from the subject image data and introduces the photographing lens into a 1 st focus allowable range based on the contrast information;

a phase difference AF device that receives the subject light beam reflected by a mirror member that enters or is disposed in an optical path of the photographing lens and detects a defocus amount of the photographing lens in a phase difference manner, the phase difference AF device guiding the photographing lens within a 3 rd focus allowable range based on a result of the detection;

a release button having a 2-stage operation manner of a half-press operation and a full-press operation; and

a control device which performs control as follows: the control device causes the 1 st contrast AF device to perform a focus adjustment operation when a half-press operation of a release button is performed during execution of the live view display operation, and causes the phase difference AF device to perform a focus adjustment operation when a full-press operation of the release button is performed thereafter.

2. The imaging apparatus according to claim 1, further comprising a 2 nd contrast AF apparatus which obtains contrast information of the object image from the object image data and introduces the imaging lens into a 2 nd focus allowable range based on the contrast information.

3. The imaging apparatus according to claim 2, wherein the control unit performs control such that: when the release button is half-pressed, the control device causes the 1 st contrast AF device to perform a focus adjustment operation, continues the half-pressing operation of the release button at the time when the 1 st focus adjustment operation is completed, and causes the 2 nd contrast AF device to perform the focus adjustment operation when the full-pressing operation is not performed.

4. The imaging apparatus according to claim 3, wherein the control unit performs control such that: when the release button is fully pressed while the 2 nd contrast AF device is performing the focus adjustment operation, the control device stops the focus adjustment operation and causes the phase difference AF device to perform the focus adjustment operation.

5. The imaging apparatus according to claim 3, wherein the control unit performs control such that: when the release button is fully pressed after the focus adjustment operation is completed by the 2 nd contrast AF device, the phase difference AF device performs the photographing operation without performing the focus adjustment operation.

6. The image capturing apparatus according to claim 2, further comprising a selection unit that selects the following mode: a 1 st focus adjustment mode in which a focus adjustment operation is performed by a combination of the 1 st contrast AF device and the phase difference AF device, and a 2 nd focus adjustment mode in which a focus adjustment operation is performed by a combination of the 1 st contrast AF device and the 2 nd contrast AF device.

7. The image capturing apparatus according to claim 6, wherein when the selection unit selects the 1 st focus adjustment mode, the control unit performs control such that: causing the 1 st contrast AF device to perform a focus adjustment operation when the release button is half-pressed, and causing the phase difference AF device to perform a focus adjustment operation when the release button is fully pressed;

when the selection unit selects the 2 nd focus adjustment mode, the control device performs control such that: and a focus adjustment control unit configured to cause the 1 st contrast AF device to perform a focus adjustment operation when the release button is half-pressed, and to cause the 2 nd contrast AF device to perform a focus adjustment operation when the release button is fully pressed.

8. The image capturing apparatus according to claim 6, further comprising a determination unit that determines whether the photographing lens is focused in a region where the depth of the scene to be photographed is shallow,

the selection unit selects the 1 st focus adjustment mode or the 2 nd focus adjustment mode according to the determination result of the determination unit.

9. The imaging apparatus according to claim 8, wherein the selection unit selects the 2 nd focus adjustment mode when the determination unit determines that the imaging lens is focused in an area where a depth of a subject scene is shallow.

10. The imaging apparatus according to claim 9, wherein the control unit performs control of: even if the release button is fully pressed before the focus adjustment operation is completed by the 2 nd contrast AF apparatus, the operation does not shift to the photographing operation.

11. The imaging apparatus according to claim 8, wherein the imaging magnification of the imaging lens is compared with a predetermined magnification, or the object distance of the imaging lens is compared with a predetermined distance, and when focusing is performed on a short distance side, it is determined that the imaging lens is located in an area where the depth of the object scene is shallow; or,

when the photographing lens is a macro lens or the photographing mode is a macro mode, it is determined that the photographing lens is located in an area where the depth of the subject scene is shallow.

12. The image capturing apparatus according to claim 2, wherein the display device performs enlarged live view display by cutting out a part of the range of the subject image data;

in the enlarged live view display, the 1 st contrast AF device and the 2 nd contrast AF device perform a focus adjustment operation based on contrast information of the cut-out object image data.

13. The image pickup apparatus according to claim 12, wherein the phase difference AF apparatus includes a sensor for detecting a defocus amount of the image pickup lens by a phase difference method for a plurality of points in an image pickup screen;

in the enlarged live view display, the phase difference AF device performs a focus adjustment operation based on the sensor included in the imaging screen on which the enlarged display is performed.

14. The imaging apparatus according to claim 12, wherein the control unit performs control such that: causing the 1 st contrast AF device to perform a focus adjustment operation based on contrast information of the cut-out object image data when the release button is half-pressed during the enlarged live view display;

when the release button is fully pressed, the 2 nd contrast AF device is caused to perform a focus adjustment operation based on the contrast information of the cut-out object image data.

15. The image pickup apparatus according to claim 2, wherein the 2 nd allowable focusing range and the 3 rd allowable focusing range are substantially equal to each other, and the 1 st allowable focusing range is wider than the 2 nd allowable focusing range.

16. The image capturing apparatus according to claim 15, wherein the 1 st focus allowable range is determined according to a display resolution of the display device or a display dot size of the display device;

the 2 nd focus allowable range and the 3 rd focus allowable range are determined according to an imaging resolution of the imaging device or a pixel size of the imaging surface.

17. A control method of a photographing apparatus for photographing an object,

shooting a subject;

performing live view display of the captured subject image;

according to the preparation operation of shooting, the contrast information according to the above-mentioned object picture guides the photographic lens into the 1 st focusing and allows the range; and

according to the shooting operation, the shooting lens is guided to the 3 rd focusing allowable range according to the defocusing information of the shooting lens.

18. A control method of a photographing apparatus for photographing an object,

shooting a subject;

performing live view display of the captured subject image;

according to the preparation operation of shooting, the contrast information according to the above-mentioned object picture guides the photographic lens into the 1 st focusing and allows the range; and

when the photographing preparation operation is continued without performing the photographing operation, the photographing lens is guided into the 2 nd focus allowable range based on the contrast information of the subject image.

19. The method of controlling an image capturing apparatus according to claim 18, wherein when the image capturing operation is performed while the image capturing lens is being introduced into the 2 nd focus allowable range, the operation of introducing the image capturing lens into the 2 nd focus allowable range is stopped, and the image capturing lens is introduced into the 3 rd focus allowable range based on the defocus information of the image capturing lens.

20. The method of controlling an image capturing apparatus according to claim 19, wherein the 2 nd allowable focusing range and the 3 rd allowable focusing range are substantially equal to each other, and the 1 st allowable focusing range is wider than the 3 rd allowable focusing range.

21. The method of controlling an image capturing apparatus according to claim 20, wherein the 1 st focus allowable range is determined according to a display resolution or a display dot size;

the 2 nd focus allowable range and the 3 rd focus allowable range are determined according to an imaging resolution or an imaging size.

22. The method of controlling a photographing apparatus according to claim 18, wherein in a case of a region where a depth of a subject scene is shallow, the photographing lens is guided within a 2 nd focus allowable range according to a photographing operation based on contrast information of the subject image;

when the shot scene is a deep area, the shooting lens is guided into the 3 rd focusing allowable range according to the shooting operation according to the defocusing information of the shooting lens.

23. The method of controlling an image capturing apparatus according to claim 18, wherein the 1 st focus allowable range is wider than the 2 nd focus allowable range.

24. A control method of a photographing apparatus for photographing an object,

shooting a subject;

cutting out a part of range of the shot object image, and carrying out enlarged live view display;

according to the shooting preparation operation, the shooting lens is guided into the 1 st focusing allowable range according to the contrast information of the shot image in the cut partial range; and

when the photographing preparation operation is continued without performing the photographing operation, the photographing lens is guided into the 2 nd focus allowable range based on the contrast information of the subject image of the cut-out partial range.

25. The method of controlling an imaging apparatus according to claim 24, wherein when an imaging operation is performed while the imaging lens is being introduced into the 2 nd focus allowable range, the operation of introducing the imaging lens into the 2 nd focus allowable range is stopped, and the imaging lens is introduced into the 3 rd focus allowable range based on defocus information of a point included in the cut partial range.

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