JP2012090217A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device that enables moving image capturing not requiring troublesome operations even in a dark scene such as a night scene requiring image capturing in a bulb mode.SOLUTION: An imaging device capable of still image capturing and moving image capturing comprises: moving image capturing instruction means (204c) for instructing the start of moving image capturing; a first moving image recording mode for recording image data obtained by driving an imaging element at a first frame rate when the start of moving image capturing is instructed by the moving image capturing instruction means; a second moving image recording mode for recording image data obtained by driving the imaging element at a frame rate lower than that in the first moving image recording mode; and subject luminance measurement means (15 or 22,39) for measuring subject luminance, and comprises control means (39) for selecting any one of the first moving image recording mode and the second moving image recording mode according to a measurement result by the subject luminance measurement means and recording a moving image.

Description

  The present invention relates to an imaging apparatus such as an electronic still camera, and more particularly to an imaging apparatus capable of still image shooting and moving image shooting.

  Conventionally, digital cameras having a moving image shooting function and video cameras having a still image shooting function have already been commercialized by improving the performance of an image compression technique and a processor.

  Among these commercialized digital cameras, when the still image shooting instruction button is operated, the exposure control parameters (shutter speed, aperture value, shooting sensitivity) set according to the shooting mode Take a picture. Also, when the movie shooting instruction button is operated, program shooting with exposure control parameters suitable for movie shooting in any shooting mode (the camera automatically sets the shutter speed and aperture value according to a predetermined program diagram) Digital cameras that can be used for shooting) have been commercialized.

  For example, Patent Document 1 discloses an imaging device that performs still image shooting and moving image shooting with exposure control parameters set in a shooting mode.

  As described above, if the still image shooting instruction button is operated, still image shooting is performed immediately, and if the moving image shooting instruction button is operated, moving image shooting is performed immediately. Troublesome operations such as mode switching are not required.

  In addition, digital video cameras that have already been commercialized have a dark place shooting mode called a so-called night mode or low light mode.

  The night mode and low light mode will be described more specifically. Normally, when displaying and recording a moving image, it is necessary to secure a frame rate of at least about 24 to 30 frames / second in order to obtain a higher resolution in the time direction. In order to maintain this frame rate, the shutter speed is controlled so as to slow down only from 1/24 s to 1/30 s even in a dark place.

  On the other hand, when the dark place shooting mode is selected, for example, even when the frame rate is lowered, the shutter speed (for example, there are digital video cameras that slow down the shutter speed to 1/2 s) is controlled to be shot (of course, the frame is shot). Since the rate drops, it ’s not smooth.) By performing such control, digital video cameras that enable shooting even in dark places have already been commercialized.

Japanese Patent Application No. 2009-119812

  In the case of the digital camera already commercialized as described above, if the moving image shooting instruction button is operated while the valve mode is set, shooting can be performed by program exposure control for moving images. That is, since moving image shooting is performed at the frame rate of about 24 frames to 30 frames / second described above, the shutter time is delayed only to 1/30 s, so that there is a problem that shooting cannot be performed in a dark place. In particular, the fact that the bulb mode is selected is often a dark scene such as a night view, so that a failed moving image is shot. Also, Patent Document 1 does not describe moving image shooting in the bulb mode.

  As a way to avoid this problem, there is a method to shoot a movie by switching to a dark place shooting mode called night mode or low light mode, but the troublesome operation of switching the mode is necessary, and the photo opportunity is missed Occurs.

  Accordingly, an object of the present invention is to provide an imaging apparatus that can perform moving image shooting without the need for troublesome operations even if the shooting mode is a dark mode such as a night view that requires shooting in the bulb mode. That is.

In order to achieve the above object, according to the present invention, in an imaging apparatus capable of still image shooting and moving image shooting, a moving image shooting instructing unit instructing start of moving image shooting is instructed to start moving image shooting by the moving image shooting instructing unit. A first moving image recording mode for recording image data obtained by driving the image sensor at a first frame rate,
A second moving image recording mode for recording image data obtained by driving the image sensor at a frame rate lower than that of the first moving image recording means;
A control unit for selecting a first moving image recording unit or a second moving image recording unit according to a measurement result of the subject luminance measuring unit and recording a moving image. It is characterized by having.

  According to the present invention, it is possible to provide an imaging apparatus capable of shooting moving images with appropriate exposure without the need for troublesome operations even in a dark scene such as a night view that requires shooting in the bulb mode. .

It is a block diagram of the imaging device concerning an embodiment of the invention. 1 is an external view of an imaging apparatus according to an embodiment of the present invention. It is a flowchart of the moving image shooting operation in the bulb mode according to the embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram of an imaging apparatus according to an embodiment of the present invention.

  Reference numeral 100 denotes a lens unit on which an interchangeable photographic lens is mounted. Reference numeral 200 denotes an imaging apparatus main body.

  The lens 5 is usually composed of a plurality of lenses, but here, only a single lens is shown for simplicity. Reference numeral 6 denotes a communication terminal for the lens unit 100 to communicate with the imaging apparatus main body 200 side, and reference numeral 10 denotes a communication terminal for the imaging apparatus main body 200 to communicate with the lens unit 100 side. The lens unit 100 communicates with the microcomputer 39 (corresponding to the control means) through the communication terminals 6 and 10, and controls the diaphragm 1 through the diaphragm driving circuit 2 by the internal lens system control circuit 4. The focus is adjusted by moving the position of the lens 5 via the AF drive circuit 3.

Reference numeral 15 denotes an AE sensor that measures the luminance of a subject (hereinafter referred to as subject luminance) that has passed through the lens unit 100. The AE sensor 15 corresponds to a field luminance measuring unit.
Reference numeral 11 denotes an AF sensor, which outputs defocus amount information to the microcomputer 39. The microcomputer 39 controls the lens unit 100 based on the defocus amount information output from the AF sensor 11.

  A quick return mirror 12 is raised and lowered by an actuator (not shown) in response to an instruction from the microcomputer 39. Reference numeral 13 denotes a focusing screen, and the user can confirm the focus and composition of the optical image of the subject obtained through the lens unit 100 by observing the focusing screen 13 through the pentaprism 14 and the finder 16.

  Reference numeral 17 denotes a focal plane shutter, and the exposure time of the image sensor 20 can be freely controlled under the control of the microcomputer 39. An optical filter 18 is generally composed of a low-pass filter or the like, and cuts a high-frequency component of light entering from the focal plane shutter 17 and guides the subject image to the image sensor 20.

  The image pickup device 20 is generally an image pickup device such as a CCD or a CMOS, and a subject image formed on the image pickup device 20 through the lens unit 100 is photoelectrically converted and captured as an electric signal. Reference numeral 21 denotes an AMP circuit that amplifies the electrical signal captured by the image sensor 20 with a gain corresponding to the set photographing sensitivity. An A / D conversion circuit 22 converts an analog signal converted into an electric signal by the image sensor 20 into a digital signal.

  An image processing circuit 23 performs filter processing, color conversion processing, and gamma / knee processing on the image data based on the output of the image sensor 20 converted into a digital signal by the A / D conversion circuit 22, and a memory controller. 27. The image processing circuit 23 also includes a D / A conversion circuit. Therefore, the image data converted into a digital signal by the A / D conversion circuit 22 or the image data input by the memory controller 27 may be converted into an analog signal and output to the liquid crystal display unit 25 via the liquid crystal drive circuit 24. Is possible. Image processing and display processing by these image processing circuits 23 are switched by the microcomputer 39. The liquid crystal display unit 25 can perform live view display that sequentially displays images based on the subject image formed on the image sensor 20. The microcomputer 39 performs white balance adjustment based on the color balance information of the captured image. Further, the microcomputer 39 uses the image data based on the output of the imaging device 20 converted into a digital signal by the A / D conversion circuit 22 to obtain luminance information of the captured subject.

  The memory controller 27 stores unprocessed image data input from the image processing circuit 23 in the buffer memory 26 or stores image processed image data in the memory 28. The memory controller 27 also takes in image data from the buffer memory 26 and the memory 28 and outputs the image data to the image processing circuit 23. The memory controller 27 stores image data sent via the external interface 29 in the memory 28, and conversely outputs the image data stored in the memory 28 to the outside via the external interface 29. Is also possible. The memory 28 may be detachable. In FIG. 1, the memory 28 is illustrated as a detachable memory. Specifically, a compact flash (registered trademark) can be used.

  Reference numeral 32 denotes a timing control circuit, through which the microcomputer 39 controls the drive timing of the image sensor 20. A power supply control circuit 35 is supplied with power from the AC power supply unit 30 or the secondary battery unit 31 and turns on / off the power in response to an instruction from the microcomputer 39. The power supply control circuit 35 also notifies the microcomputer 39 of information on the current power supply state detected by the power supply state detection circuit 34 and information on the current power supply type detected by the power supply type detection circuit 33. . Reference numeral 36 denotes a shutter control circuit, through which the microcomputer 39 controls the focal plane shutter 17. An optical filter vibration control circuit 37 is a circuit that vibrates the piezoelectric element 19 connected to the optical filter 18. It vibrates according to the instruction of the microcomputer 39 so that the piezoelectric element is vibrated at predetermined values for the vibration amplitude, vibration time, and vibration axial direction.

  Reference numeral 38 denotes a non-volatile memory (EEPROM) which can store exposure control values and data arbitrarily set by the user, such as shutter speed, aperture value, and shooting sensitivity, even when the camera is not turned on.

  2A and 2B are external views of the lens unit 100 and the imaging apparatus main body 200. FIG. 2A is a front external view, and FIG. 2B is a rear external view. In FIG. 2, parts common to FIG. 1 are denoted by the same symbols.

Reference numeral 201 denotes a release button that, when pressed halfway, instructs the start of a photometric operation for measuring the subject brightness or a focusing operation for focusing on the subject. Further, when the release button 201 (still image shooting instruction button) is fully pressed, the start of still image shooting is instructed, and an image is shot.
Reference numeral 202 denotes a mode dial (corresponding to a valve mode setting means) for setting the shooting mode of the image pickup apparatus. The user operates the mode dial 202 to set shooting modes such as a sports mode and a landscape mode. As other shooting modes, a manual mode in which the user can set the shutter speed and aperture value at the time of shooting, and a Tv priority mode in which exposure control is automatically performed while maintaining the shutter speed set by the user can be set. Further, a so-called valve mode is provided in which the focal plane shutter 17 is kept open (that is, exposure to the image sensor 20 is continued) while the release button 201 is half-pressed.

  Reference numeral 203 denotes an electronic dial. The user operates the electronic dial 203 to set exposure control values such as shutter speed and aperture value.

  Reference numeral 204 denotes a cross key and a setting button. When the user selects the setting contents displayed on the liquid crystal display unit 25 or a thumbnail image, the selection range moves in the horizontal direction by pressing 204a, and the vertical direction by pressing 204b. The selection range moves to. The selected content is set by pressing 204c at the selected location. The setting button 204c also functions as a moving image shooting instruction button (corresponding to moving image shooting instruction means) for instructing start and stop of moving image shooting. Reference numeral 205 denotes a power switch. The user turns the power on / off by turning the power switch.

  Reference numeral 206 denotes a switch group for performing various settings. These switch groups include a playback instruction button for displaying an image stored in a recording medium inside and outside the camera on the liquid crystal display unit 25, a setting screen display instruction button for displaying various setting screens on the liquid crystal display unit 25, and the like. There is. By pressing these switches, the user can display a setting screen for performing various settings, check a captured image, and the like.

  Reference numeral 207 denotes a live view instruction button for instructing start of a live view operation. When this button is pressed by the user, the imaging apparatus transitions to a live view state and displays a live view image on the liquid crystal display unit 25.

  Hereinafter, with reference to FIG. 3, a flowchart of the moving image shooting operation in the bulb mode of the imaging apparatus according to the present embodiment will be described.

First, in step S101, the microcomputer 39 determines whether or not the setting button 204c as a moving image shooting instruction button for instructing the start of moving image shooting is pressed. If it is pressed, the microcomputer 39 proceeds to step S102 and is not pressed. If so, the operation in step S101 is repeated.
In step S <b> 102, the microcomputer 39 acquires field luminance information from the AE sensor 15. Then, a predetermined calculation is performed from the acquired field luminance information, the aperture value manually set by the user in advance, and the photographing sensitivity manually set by the user or automatically set by the microcomputer 39, and an appropriate shutter is obtained. The speed is calculated and the process proceeds to step S103.

  In step S103, the microcomputer 39 determines whether the shutter speed calculated in step S102 is faster or slower than 1/30 s. When it is determined that it is faster than 1/30 s, the process proceeds to step S104, and the moving image shooting program mode (corresponding to the first moving image recording mode) is set. In other words, since the frame rate is 30 frames / s or more as usual, smooth moving image shooting is possible.

  On the other hand, when it is determined in step S103 that the shutter speed is slower than 1/30 s, the process proceeds to step S105, and the dark place shooting program mode (corresponding to the second moving image recording mode) is set. That is, shooting is performed at a reduced frame rate according to the shutter speed. By lowering the frame rate in this way, it is possible to shoot at a slow shutter speed, and for example, it is possible to shoot a moving image with an appropriate exposure amount even in a dark scene such as night scene shooting.

  When the processing of step S104 and step S105 is completed, the process proceeds to step S106.

  In step S106, in response to an instruction from the microcomputer 39, the quick return mirror 12 is raised by an actuator (not shown).

  In step S107, the aperture value manually set by the user is transmitted from the microcomputer 39 to the lens system control circuit 4 via the communication terminals 6 and 10. The lens system control circuit 4 controls the diaphragm 1 via the diaphragm driving circuit 2 based on the transmitted diaphragm value.

  In step S108, in response to an instruction from the microcomputer 39, the focal plane shutter 17 is opened and exposure of the image sensor 20 is started.

  In step S109, the microcomputer 39 controls the drive timing of the image sensor 20 via the timing control circuit 32 based on the shutter speed calculated in step S102. Further, the AMP circuit 21 amplifies the photographic signal with a gain corresponding to the photographic sensitivity set manually by the user or automatically set by the microcomputer 39, and converts it into a digital signal via the A / D conversion circuit 22. . Then, the image data converted into the digital signal is taken into the buffer memory 26 via the image processing circuit 23. Thereafter, recording is performed in the memory 28.

  In step S 110, the image data captured in the buffer memory 26 is converted into an analog signal via the memory controller 27, and the converted analog signal is output to the liquid crystal display unit 25 via the liquid crystal drive circuit 24.

  In step S111, the microcomputer 39 determines whether or not moving image shooting is in progress (that is, determines again whether the setting button 204c as the moving image shooting instruction button has been pressed). If moving image shooting is in progress, the process returns to step S109. If a movie is not being shot, the series of movie shooting processes is terminated.

  Note that the operations in steps S109 to S111 are repeated at time intervals that match the set frame rate.

  As described above, even when the valve mode is set, moving image shooting can be started quickly by pressing the moving image shooting instruction button, so that the problem of missing a photo opportunity for moving image shooting can be avoided.

  In addition, since the moving image program and the dark place shooting program are selectively used according to the field luminance, it is possible to appropriately shoot with exposure in any scene.

  In the present embodiment, the AE sensor 15 is used as the subject brightness measuring means for measuring the subject brightness. However, the image based on the output of the imaging element 20 converted into a digital signal by the A / D conversion circuit 22 by the microcomputer 39. The luminance information of the imaged subject may be obtained using the data. In this case, the microcomputer 39 and the A / D conversion circuit 22 constitute subject brightness measuring means.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

15 AE sensor 20 Image sensor 21 AMP circuit 22 A / D conversion circuit 23 Image processing circuit 39 Microcomputer 202 Mode dial 204c Movie shooting instruction button

Claims (3)

In an imaging device capable of still image shooting and movie shooting,
Moving image shooting instruction means (204c) for instructing start of moving image shooting;
A first moving image recording mode for recording image data obtained by driving the image sensor at a first frame rate when instructed to start moving image shooting by the moving image shooting instruction means;
A second moving image recording mode for recording image data obtained by driving the image sensor at a frame rate lower than that of the first moving image recording means;
Subject brightness measuring means (15 or 22, 39) for measuring subject brightness,
An imaging device comprising: control means (39) for selecting one of the first moving image recording means and the second moving image recording means and recording a moving image in accordance with a measurement result of the subject luminance measuring means. apparatus. Valve mode setting means (202) capable of setting the valve mode,
When the valve mode is set by the valve mode setting unit, either the first moving image recording mode or the second moving image recording mode is selected according to the measurement result of the subject luminance measuring unit according to the subject luminance. The image pickup apparatus according to claim 1, further comprising a control means (39) for recording a moving image. When it is determined that the shutter speed is faster than a predetermined value as a result of the measurement by the subject luminance measuring unit, the first moving image recording unit records a moving image, and the measurement result of the subject luminance measurement unit and the shutter speed is lower than the predetermined value. The imaging apparatus according to claim 1, further comprising a control unit (39) that performs moving image recording by the second-order moving image recording unit when it is determined to be late.