JP4708595B2 - Imaging apparatus and camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging device, a camera, and a control method of the imaging device, and more specifically, an imaging device that receives a light beam that passes through a different position of a pupil of a photographing lens and enables focus detection of a pupil division method, The present invention relates to a camera equipped with the imaging device and a method for controlling the imaging device.
[0002]
[Prior art]
As one of methods for detecting the focus state of a photographing lens, an apparatus that performs pupil division type focus detection using a two-dimensional sensor in which a microlens is formed in each pixel of the sensor is disclosed in Japanese Patent Application Laid-Open No. 55-1111928. And JP-A-58-24105.
[0003]
Japanese Patent Application No. 11-306815 proposes a device that performs pupil division type focus detection using a CMOS image sensor (imaging device) used in a digital still camera.
[0004]
FIG. 16 is a diagram for explaining the principle of a pupil division type focus detection method using an image sensor proposed in Japanese Patent Application No. 11-306815, and FIG. 17 is a schematic plan view showing a part of the pixel layout of the image sensor. It is. The image sensor 10 is disposed on the planned imaging plane of the photographic lens 5. Each pixel of the image sensor 10 includes two photoelectric conversion regions 13α and 13β, and the photoelectric conversion regions 13α and 13β are formed on the photographing lens 5 by the microlens 11 formed on the photographing lens side of each photoelectric conversion region. It is set so as to have a substantially image-forming relationship with the pupil.
[0005]
Here, the photoelectric conversion region 13α receives a light beam that passes through the upper part of the pupil of the photographing lens 5 in the figure, and the photoelectric conversion region 13β receives a light beam that passes through the lower part of the pupil of the photographing lens 5 in the figure. At the time of focus detection, as shown in FIG. 17, the outputs from the photoelectric conversion region α and the photoelectric conversion region β are read out independently, and further, an image by a light beam transmitted through different pupil positions of the photographing lens from the outputs from a plurality of pixels. Generated.
[0006]
A method of performing focus detection using an image generated from a light beam transmitted through a different pupil position of the photographing lens is a known technique as disclosed in JP-A-5-127074.
[0007]
On the other hand, during normal photographing, the outputs of the photoelectric conversion region 13α and the photoelectric conversion region 13β are added and output within the pixel.
[0008]
By the way, as exposure control of a CMOS image sensor, Japanese Patent Application Laid-Open No. 5-75931 discloses an exposure control method for a random access image sensor. In this publication, an exposure control method is disclosed in which an exposure time is set longer in an area where the amount of illumination light is small.
[0009]
Further, in the CMOS image sensor used in the conventional focus detection apparatus, when a captured image is always displayed by an electronic viewfinder or the like, accumulation time control is performed by a rolling shutter method. In the case of the rolling shutter system, one line of the image sensor is controlled with the same accumulation time.
[0010]
[Problems to be solved by the invention]
However, as shown in FIG. 16, the photoelectric conversion regions 13α and 13β of the image sensor 10 receive light beams that pass through different positions of the pupil of the photographing lens 5, so that in the peripheral region of the photographing screen, a so-called COS4 power law is established. As a result, an output imbalance occurs between the photoelectric conversion regions 13α and 13β.
[0011]
FIG. 18 shows an example of outputs of the photoelectric conversion region α and the photoelectric conversion region β on one line of the image sensor 10 when a subject with uniform luminance is viewed. In the central region (around the optical axis), the output difference between the photoelectric conversion region α and the photoelectric conversion region β is small, but a larger output difference is generated as it goes to the periphery. FIG. 19 shows line images detected in the photoelectric conversion region α and the photoelectric conversion region β in the region δ of FIG. In order to detect the focus state of the photographic lens, the correlation between the image Iα and the image Iβ must be taken. However, due to the output difference, the degree of coincidence between the two images is lowered, and the focus detection accuracy is lowered. there were.
[0012]
Therefore, in Japanese Patent Laid-Open No. 3-214133, light amount distribution information such as a decrease in peripheral light amount of the photographing lens is obtained, and processing corresponding to the light amount distribution information is performed on the subject image signal detected by the photoelectric conversion unit, A focus detection device that detects the defocus amount of a photographic lens is disclosed.
[0013]
However, when the output difference between the photoelectric conversion region α and the photoelectric conversion region β of the image sensor is large, the output image of the photoelectric conversion region having a low output in order to match the level of the output image signal of the photoelectric conversion region α and the photoelectric conversion region β. When the signal is amplified, the noise component is also amplified, and there is a drawback that a highly accurate focus detection result cannot be obtained.
[0014]
Furthermore, in the case of a digital camera system in which the photographic lens can be replaced, the output characteristics differ from those shown in FIG. 18 depending on the photographic lens attached to the camera. It was.
[0015]
Furthermore, as shown in FIG. 18, since the output difference between the photoelectric conversion region α and the photoelectric conversion region β is different if the region from which the image output is extracted differs on the same line, the focus detection accuracy varies depending on the region where focus detection is performed. was there.
[0016]
The present invention has been made in view of the above problems, and even when the amount of light incident on each photoelectric conversion area of the same pixel is different, control is performed so that the outputs of the respective photoelectric conversion areas are substantially equal, thereby detecting the focus. The purpose is to improve the accuracy.
[0018]
[Means for Solving the Problems]
To achieve the above objective The imaging device of the present invention that photoelectrically converts an optical image incident through a detachable photographic lens has two photoelectric conversion means for receiving light that has passed through one microlens in each pixel. In a two-dimensional area that includes the optical axis of the connected photographic lens Multiple Distributed Pixels, Said Shooting lens When extracting a signal for adjusting the focus of the photographic lens, in the two-dimensional area including the optical axis of the photographing lens Of the two photoelectric conversion means in the plurality of pixels, the one near the optical axis of the photographing lens each The charge accumulation time of the photoelectric conversion means is each The side closer to the optical axis of the photographic lens so as to be shorter than the charge accumulation time of the photoelectric conversion means. each The photoelectric conversion means is provided on the side far from the optical axis of the photographing lens by the first transfer pulse. each The photoelectric conversion means has control means for controlling each of them independently by the second transfer pulse.
[0020]
According to another preferred embodiment, each pixel has two photoelectric conversion means for receiving light that has passed through one microlens. In a two-dimensional area that includes the optical axis of the connected photographic lens Multiple Distributed Pixels, In a two-dimensional area including the optical axis of the photographing lens Of the two photoelectric conversion means in the plurality of pixels, the one near the optical axis of the photographing lens each The photoelectric conversion means is provided on the side far from the optical axis of the photographing lens by the first transfer pulse. each The photoelectric conversion means is a control means for controlling each independently by the second transfer pulse, and In a two-dimensional area including the optical axis of the photographing lens Of the photoelectric conversion means of the plurality of pixels, the side closer to the optical axis of the photographing lens each A first amplifying unit that applies a first gain to a signal obtained from the photoelectric conversion unit; and a photoelectric conversion unit of the plurality of pixels that is farther from the optical axis of the photographing lens. each Second amplifying means for applying a second gain larger than the first gain to the signal output from the photoelectric conversion means, and the control means is further adapted to the photographic lens, The first and second gains are controlled.
[0021]
In order to achieve the above object, a camera according to the present invention includes any one of the above imaging devices.
[0022]
According to a preferred aspect of the present invention, the image sensor further includes a focus detection unit that detects a focus state of the photographing lens based on signals output from two photoelectric conversion regions of each pixel of the imaging device, and the control According to the position of the focus detection area on the imaging device used by the focus detection means, Said The first and second gains are controlled.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0027]
<First Embodiment>
FIG. 1 is a schematic configuration diagram of a camera according to the first embodiment provided with an imaging apparatus (hereinafter referred to as “image sensor”) of the present invention.
[0028]
In FIG. 1, the same reference numerals are assigned to the same components as those shown in FIG. Reference numeral 10 denotes an image sensor (imaging device), which is disposed on a planned imaging plane of a photographing lens 5 of a digital still camera main body (hereinafter referred to as “camera main body”) 1. The camera body 1 includes a CPU 20 that controls the entire camera, an image sensor control circuit 21 that drives and controls the image sensor 10, an image processing circuit 24 that performs image processing on an image signal captured by the image sensor 10, and an image signal that has undergone image processing. A liquid crystal display element 9 to be displayed, a liquid crystal display element driving circuit 25 for driving the liquid crystal display element 9, an eyepiece 3 for observing a subject image displayed on the liquid crystal display element 9, and an image captured by the image sensor 10 are recorded. A memory circuit 22 and an interface circuit 23 for outputting an image processed by the image processing circuit 24 to the outside of the camera are included. The memory circuit 22 also stores information specific to the photographic lens (open F value, exit window information, etc.).
[0029]
The photographic lens 5 is detachable from the camera body 1 and is shown with two lenses 5a and 5b for convenience. However, the photographic lens 5 is actually composed of a large number of lenses, and is a focus sent from the CPU 20 of the camera body 1. The adjustment information is received by the lens CPU 50 via the electrical contact 26 and adjusted to the in-focus state by the photographing lens driving mechanism 51 based on the focus adjustment information. Reference numeral 53 denotes an aperture device, which is adjusted to a predetermined aperture value by an aperture drive mechanism 52. The CPU 20 also performs focus detection.
[0030]
FIG. 2 is a cross-sectional view of one pixel of a CMOS image sensor used for the image sensor 10 in the first embodiment of the present invention. In the figure, 117 is a p-type well, 118 is a MOS gate insulating film, SiO. ₂ It is a membrane. 126α and 126β are the surface p ₊ The n layers 125α and 125β constitute the photoelectric conversion units 101α and 101β, respectively. Reference numerals 120α and 120β denote transfer gates for transferring the photoelectric charges accumulated in the photoelectric conversion units 101α and 101β to a floating diffusion unit (hereinafter referred to as “FD unit”) 121. 129 is a color filter, 130 is a microlens, and the microlens 130 is formed in a shape and position so that the pupil of the photographing lens 5 and the photoelectric conversion unit 101 of the image sensor 10 are substantially conjugate.
[0031]
The photoelectric conversion units 101α and 101β are formed in two regions, an α region and a β region (hereinafter referred to as “photoelectric conversion region α and photoelectric conversion region β”, respectively) with the FD unit 121 interposed therebetween. Furthermore, transfer gates 120α and 120β are formed for transferring the photoelectric charges generated in the photoelectric conversion regions α and the photoelectric conversion regions β to the FD unit 121, respectively.
[0032]
During normal photographing, the photoelectric charges generated in the photoelectric conversion region α and the photoelectric conversion region β are transferred to the FD unit 121 via the transfer gates 120α and 120β and controlled to be added. On the other hand, when the focus state of the photographic lens 5 is detected, transfer of photoelectric charges from the photoelectric conversion region α and the photoelectric conversion region β to the FD unit 121 is performed independently, and a transfer gate is used so that the photoelectric charges are not added. 120α and 120β are controlled.
[0033]
FIG. 3 is a plan view schematically showing one line of the image sensor 10 according to the first embodiment of the present invention, and the shaded center pixel is a pixel on the optical axis of the photographing lens 5. Is shown. The two photoelectric conversion regions α and β in each pixel of the image sensor 10 can be controlled independently of the photoelectric conversion region on the side closer to the pixel on the optical axis of the photographing lens 5 and the photoelectric conversion region on the far side. It is comprised so that.
[0034]
That is, among the two photoelectric conversion regions in each pixel, the photoelectric conversion region β close to the central pixel in the pixel on the left side of the central pixel in the drawing and the photoelectric conversion region close to the central pixel in the pixel on the right side of the central pixel α is controlled at the same timing. Similarly, of the two photoelectric conversion regions in each pixel, the photoelectric conversion region α far from the center pixel on the left side of the center pixel in FIG. 3, and the photoelectric conversion region β far from the center pixel in the pixel on the right side of the center pixel Are controlled at the same timing.
[0035]
FIG. 4 is a schematic circuit diagram of the image sensor 10 according to the first embodiment of the present invention. In FIG. 4, a two-column × two-row two-dimensional area sensor is shown for simplification of the drawing, but actually it is composed of pixels of several million pixels.
[0036]
In FIG. 4, 101 is a photoelectric conversion unit, 103 is a transfer switch MOS transistor, 104 is a reset MOS transistor, 105 is a source follower amplifier MOS transistor, 106 is a horizontal selection switch MOS transistor, 107 is a source follower load MOS transistor, 108 Is a dark output transfer MOS transistor, 109 is a light output transfer MOS transistor, 110 is a dark output storage capacitor CTN, 111 is a light output storage capacitor CTS, 112 is a horizontal transfer MOS transistor, 113 is a horizontal output line reset MOS transistor, and 114 is a difference. It is a dynamic amplifier. A horizontal scanning circuit 115 and a vertical scanning circuit 116 constitute the image sensor control circuit 21 shown in FIG.
[0037]
In FIG. 4, the left pixel (0th pixel) in the first line corresponds to the leftmost pixel shown in FIG. 3, and the right pixel (ith pixel) in the first line corresponds to the rightmost pixel in FIG. ing. Further, the optical axis of the taking lens 5 exists between the 0th pixel and the i-th pixel.
[0038]
In each pixel, the transfer switch 103β0 and the transfer switch 103αi corresponding to the photoelectric conversion unit on the side close to the optical axis of the photographing lens 5, for example, the photoelectric conversion unit 101β0 of the 0th pixel and the photoelectric conversion unit 101αi of the i-th pixel, It is configured to be controlled by the same control pulse ΦTXα0. Further, in each pixel, the transfer switch 103α0 and the transfer switch 103βi corresponding to the photoelectric conversion unit far from the optical axis of the photographic lens 5, for example, the photoelectric conversion unit 101α0 of the 0th pixel and the photoelectric conversion unit 101βi of the i-th pixel, It is configured to be controlled by the same control pulse ΦTXβ0.
[0039]
Next, the operation of the image sensor 10 will be described using the timing chart of FIG. Since the camera 1 having the CMOS image sensor 10 of the present invention is configured so that an image taken by the image sensor 10 can be observed with the liquid crystal display element 9 at all times, accumulation control of a rolling shutter system is performed.
[0040]
FIG. 5 shows a timing chart of the 0th line when focus detection is performed by the image sensor 10. When the focus state of the photographic lens 5 is detected, the correlation calculation of two images obtained from the respective outputs of the photoelectric conversion area α and the photoelectric conversion area β of each pixel is performed, and the photographic lens is calculated from the image shift amount of the two images. 5 are detected, and the accumulation times of the photoelectric conversion region α and the photoelectric conversion region β are set so that the outputs of the two images are substantially equal in the set focus detection region. Actually, out of the two photoelectric conversion regions in one pixel, the accumulation time of the photoelectric conversion region farther from the optical axis of the photographing lens 5 is longer than the photoelectric conversion region closer to the optical axis of the photographing lens 5. Thus, the control pulses ΦTXα0 and ΦTXβ0 are controlled. Control pulses ΦTXα0 and ΦTXβ0 are generated by the vertical scanning circuit 116.
[0041]
First, the reading of the photoelectric charge in the photoelectric conversion region on the side close to the optical axis of the photographing lens 5 is executed. The horizontal selection switch MOS transistor 106 is turned on by setting the control pulse ΦS0 to high, and the pixel portion of the 0th line is selected. Next, the control pulse ΦR0 is set to low to stop the resetting of the FD unit 121, the FD unit 121 is brought into a floating state, and the gate-source between the source follower amplifier MOS transistor 105 is set to through. The dark voltage of the FD unit 121 is output to the storage capacitor 110 by the source follower operation. Here, the dark voltage of the 0th pixel portion of the 0th line is output to the storage capacitor 110β0, and the dark voltage of the i th pixel portion is output to the storage capacitor 110αi.
[0042]
Next, in order to output the photoelectric conversion region on the side close to the optical axis of the photographing lens of the 0th line, the control switch ΦTXα0 is set to high, the transfer switch MOS transistor 103 is turned on, and the photogenerated carrier is transferred to the FD unit 121. . The electric charge from the photoelectric conversion unit 101 of the photodiode is transferred to the FD unit 121, so that the potential of the FD unit 121 changes according to light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD unit 121 is output to the storage capacitor 111 with the control pulse ΦTSα being high. Here, the light output of the 0th pixel portion of the 0th line is output to the storage capacitor 111β0, and the light output of the i-th pixel portion is output to the storage capacitor 111αi. At this time, the dark output and the light output of the photoelectric conversion region on the side near the optical axis of the photographing lens of each pixel of the 0th line are stored in the storage capacitors 110 and 111, respectively.
[0043]
Next, in order to perform accumulation control so that the accumulation time of the photoelectric conversion area on the side closer to the optical axis of the photographing lens 5 is shorter by Δt relative to the accumulation time of the photoelectric conversion area on the side far from the optical axis of the photographing lens. First, after Δt time when the control pulse ΦTXα0 is set to high, the control pulse ΦTXα0 is set to high again to turn on the transfer switch MOS transistor 103, and the photocharge generated and stored at time Δt is transferred to the FD unit 121. At this time, if the control pulse ΦR0 is set high, the charge in the FD portion 121 disappears. Further, if the transfer switch MOS transistor 103 is closed by setting the control pulse ΦTXα0 to low, photocharge re-accumulation is started in the photoelectric conversion region on the side closer to the optical axis of the photographing lens, and the light charge is read until the photocharge is read again. Charge is accumulated.
[0044]
Subsequently, the reading of the photoelectric charge in the photoelectric conversion region on the side far from the optical axis of the photographing lens is executed. The horizontal selection switch MOS transistor 106 is turned on by setting the control pulse ΦS0 to high, and the pixel portion of the 0th line is selected. Next, the control pulse ΦR0 is set low, the reset of the FD unit 121 is stopped, the FD unit 121 is set in a floating state, the gate-source between the source follower amplifier MOS transistor 105 is set to through, and the control pulse ΦTNβ is set high after a predetermined time. The dark voltage of the FD unit 121 is output to the storage capacitor 110 by the source follower operation. Here, the dark voltage of the 0th pixel portion of the 0th line is output to the storage capacitor 110α0, and the dark voltage of the i th pixel portion is output to the storage capacitor 110βi.
[0045]
Next, in order to output the photoelectric conversion region on the side far from the optical axis of the photographic lens of each pixel in the 0th line, the transfer switch MOS transistor 103 is turned on by setting the control pulse ΦTXβ0 to high, and the photocharge is transferred to the FD unit 121. Forward. The electric charge from the photoelectric conversion unit 101 of the photodiode is transferred to the FD unit 121, so that the potential of the FD unit 121 changes according to light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD unit 121 is output to the storage capacitor 111 with the control pulse ΦTSβ being high. Here, the light output of the 0th pixel portion of the 0th line is output to the storage capacitor 111α0, and the light output of the i th pixel portion is output to the storage capacitor 111βi. At this time, the dark output and the light output of the photoelectric conversion region on the side far from the optical axis of the photographing lens of each pixel in the 0th line are stored in the storage capacitors 110 and 111, respectively. If the transfer switch MOS transistor 103 is closed by setting the control pulse ΦTXβ0 to low, photocharge accumulation is started in the photoelectric conversion region far from the optical axis of the photographic lens, and the photocharge is accumulated until the photocharge is read again. The
[0046]
The photoelectric charges generated in the photoelectric conversion unit 101 are first read out from the photoelectric conversion region on the side close to the optical axis of the photographing lens 5 to the storage capacitor 111 in each pixel, and then on the side far from the optical axis of the photographing lens 5. Although control is performed so that the storage capacitor 111 reads from the photoelectric conversion region, the output from the image sensor 10 is divided into the photoelectric conversion regions of each pixel so that subsequent signal rearrangement processing is not required. The horizontal scanning circuit 115 controls so that the photoelectric conversion regions in the same direction are sequentially output.
[0047]
As for the output from the image sensor 10, the horizontal output line reset MOS transistor 113 is turned on by setting the control pulse ΦHC temporarily high to reset the horizontal output line, and to the horizontal transfer MOS transistor 112 of the horizontal scanning circuit 115 in the horizontal transfer period. Are output to the horizontal output line by the scanning timing signal. The horizontal scanning circuit 115 first generates a scanning timing signal so as to output the light output of the photoelectric conversion region α among the photoelectric conversion regions of each pixel. As a result, the storage capacitors from the storage capacitor 111α0 to the storage capacitor 111αi are output to the outside of the image sensor. Subsequently, the horizontal scanning circuit 115 generates a scanning timing signal so as to output the light output of the photoelectric conversion region β in the photoelectric conversion region of each pixel. As a result, the storage capacitors from the storage capacitor 111β0 to the storage capacitor 111βi are output to the outside of the image sensor 10. At this time, since the differential amplifier 114 takes the differential output Vout of the storage capacitors 110 and 111, a signal with good S / N from which random noise and fixed pattern noise of the pixel are removed can be obtained.
[0048]
The output from the image sensor 10 is shaped as a focus detection image signal by the CPU 20 that performs focus detection processing.
[0049]
FIG. 6 shows the outputs of the photoelectric conversion regions α and β of each pixel on the 0th line when a subject with uniform brightness is photographed. Since an accumulation time difference of Δt0 is provided between the photoelectric conversion region on the side closer to the optical axis of the photographic lens and the photoelectric conversion region on the far side, the outputs from the photoelectric conversion regions in the focus detection regions δ1 and δ2 in FIG. It has become.
[0050]
FIG. 7 shows an example of an image for focus detection detected in the focus detection areas δ1 and δ2 of FIG. 6 when the subject is a single line, for example. The outputs of the focus detection image signals Iα and Iβ are substantially the same. As a result, the degree of correlation between the two image signals is high, and high-precision focus detection can be performed.
[0051]
When the CPU 20 accurately detects the focus state of the photographic lens 5 based on the focus detection signal output from the image sensor 10, the CPU 20 sets an electrical contact 26 provided between the camera body 1 and the photographic lens 5. The defocus information of the photographing lens 5 is transmitted to the lens CPU 50 through the lens CPU 50. The lens CPU 50 converts the defocus information received from the CPU 20 of the camera body 1 into a photographing lens driving amount and transmits the lens driving mechanism 51 to adjust the focus state of the photographing lens 5.
[0052]
When the focus detection is to be performed in a region different from the 0th line and different from the focus detection regions δ1 and δ2 in FIG. 6, photoelectric conversion on the side close to the optical axis of the photographing lens of each pixel of the image sensor 10 is performed. Since the difference in received light amount differs between the area and the far side photoelectric conversion area, different accumulation time control is required.
[0053]
For example, as shown in FIG. 8, when focus detection is to be performed in the focus detection regions δ3 and δ4 outside the focus detection regions δ1 and δ2 with respect to the optical axis of the photographic lens 5, the side closer to the optical axis of the photographic lens. Since the difference in the amount of received light between the photoelectric conversion region and the far side photoelectric conversion region becomes larger, the accumulation time of the far side photoelectric conversion region with respect to the photoelectric conversion region closer to the optical axis of the photographing lens 5 is made longer. To be controlled.
[0054]
FIG. 9 is a diagram for explaining that the output signals of the photoelectric conversion region near the optical axis of the photographing lens 5 in the focus detection regions δ3 and δ4 in FIG. The timing chart of a line is shown. The circuit configuration of the image sensor at this time is the same as that in FIG.
[0055]
In FIG. 9, what is different from the timing chart of the 0th line in FIG. 5 is the time of each control pulse. Since the focus detection area of the j-th line is set on the outer side with respect to the optical axis of the photographing lens 5, the accumulation time of the photoelectric conversion area on the side closer to the optical axis of the photographing lens and the photoelectric conversion area on the far side The ratio is
(T0−Δt0) / t0> (tj−Δtj) / tj
[0056]
, The vertical scanning circuit 116 controls each control pulse.
Further, as is apparent from FIG. 16, the received light amount of the photoelectric conversion area closer to the optical axis of the photographic lens and the farther photoelectric conversion area depending on the open F value and the exit window of the photographic lens 5 attached to the camera body 1. The difference changes. FIG. 10 is a flowchart for setting the accumulation time ratio of each photoelectric conversion area of the image sensor 10 by the photographing lens attached to the camera body 1. Hereinafter, a description will be given with reference to the flowchart of FIG.
[0057]
The CPU 20 of the camera body 1 tries to communicate with the lens CPU 50 via the electrical contact 26 with the photographing lens 5 (step S201). If the photographing lens 5 is attached to the camera 1 and communication with the lens CPU 50 is possible (YES in step S201), the camera CPU 20 checks the type (ID) of the attached photographing lens 5 (step S202). When the type of the photographic lens mounted is confirmed, the CPU 20 confirms unique information such as the open F value and exit window information of the photographic lens stored in the memory circuit 22 (step S203). Further, the camera CPU 20 uses the information such as the open F value of the photographic lens 5 mounted, the position of the exit window, the diameter of the exit window, the position of the focus detection area on the image sensor 10 and the like to use the image sensor for focus detection. The gravity center position on the pupil of the photographing lens 5 of the received light beam received by each of the ten photoelectric conversion regions is calculated (step S204). Furthermore, the camera CPU 20 determines the angle formed between the straight line connecting the position of the center of gravity of the received light flux received by the photoelectric conversion regions α and β on the pupil of the photographing lens 5 and the photoelectric conversion regions α and β and the perpendicular of the image sensor 10. θα and θβ are calculated (step S204) (see FIG. 16). Here, the ratio of the amount of received light between the photoelectric conversion region α and the photoelectric conversion region β is approximately
COS4 (θα): COS4 (θβ)
[0058]
It becomes.
For example, when the photoelectric conversion area near the optical axis of the photographic lens is the photoelectric conversion area α and the photoelectric conversion area far from the optical axis of the photographic lens is the photoelectric conversion area β, the timing chart shown in FIG. When the sensor 10 is subjected to accumulation control, the CPU 20
[0059]
(Tj−Δtj) / tj = COS4 (θβ) / COS4 (θα)
When the accumulation time of the image sensor 10 is controlled at the accumulation time ratio set as described above, the output levels of the two focus detection image signals in the predetermined focus detection area become substantially equal, and the two focus detection images are used. The focus detection using the image signal can obtain a highly accurate result.
[0060]
Here, an example in which unique information such as the open F value of the photographing lens and exit window information is stored in the memory circuit 22 provided in the camera body 1 is shown. However, the system stores the information in the memory circuit associated with the lens CPU 50. It doesn't matter.
[0061]
FIG. 11 is a timing chart of the 0th line when the image sensor 10 performs normal imaging. During normal imaging, the photoelectric charges generated in the photoelectric conversion regions α and β are simultaneously transferred to the FD unit 121, added, and output to the outside of the image sensor 10.
[0062]
In FIG. 11, the horizontal selection switch MOS transistor 106 is turned on by setting the control pulse ΦS0 to high by the timing output from the vertical scanning circuit 116, and the pixel portion of the 0th line is selected. Next, the control pulse ΦR0 is set to low to stop the resetting of the FD unit 121, the FD unit 121 is set to the floating state, the source-follower amplifier MOS transistor 105 is set to the through state, and the control pulse ΦTNβ is set to high after a predetermined time. , The dark voltage of the FD unit 121 is output to the conductive one of the storage capacitors 110α and 110β by the source follower operation.
[0063]
Next, in order to output the two photoelectric conversion regions α and β of each pixel of the 0th line, the control pulses ΦTXα0 and ΦTXβ0 are set to high to turn on the transfer switch MOS transistors 103α and 103β. At this time, the photoelectric charges generated in the photoelectric conversion units 101α and 101β are transferred to the FD unit 121. As charges from the photoelectric conversion units 101α and 101β of the photodiode are transferred to the FD unit 121, the potential of the FD unit 121 changes according to light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD section 121 is output to the conductive one of the storage capacitors 110α and 111β with the control pulse ΦTSβ being high. At this time, the dark output and the light output of each pixel on the 0th line are stored in the storage capacitors 110α or 110β and 111α or 111β, respectively. Further, the horizontal output line reset MOS transistor 113 is turned on by setting the control pulse ΦHC temporarily high to reset the horizontal output line, and the horizontal output line is set to the horizontal output line by the scanning timing signal to the horizontal transfer MOS transistor 112 of the horizontal scanning circuit 115 in the horizontal transfer period. A dark output and a light output of the pixel are output. At this time, since the differential output Vout is obtained by the differential amplifier 114 with respect to the charges stored in the storage capacitors 110α and 111α or 110β and 111β, the S / N with good random noise and fixed pattern noise is removed. A signal is obtained.
[0064]
Subsequently, the monitor output of each pixel is detected by the scanning timing signal to the horizontal transfer MOS transistor of each pixel by the horizontal scanning circuit 115. Further, the vertical scanning circuit 116 similarly outputs all pixels of the image sensor 10 by outputting the next line.
[0065]
In the first embodiment, an example is shown in which control is performed so that the accumulation times of the two photoelectric conversion regions of each pixel are the same during normal imaging. However, as shown in the timing chart of FIG. Depending on the attached lens, the photoelectric conversion area closer to the optical axis of the photographic lens and the photoelectric conversion area farther from the optical axis of the photographic lens are controlled so that the accumulation times are different, and added and output within each pixel. By doing so, it is also effective to minimize the output imbalance due to a decrease in the light amount at a position away from the optical axis.
[0066]
<Second Embodiment>
Next, a second embodiment of the present invention will be described. In the first embodiment, the signal difference between the image signals Iα and Iβ shown in FIG. 19 is adjusted by changing the accumulation times in the photoelectric conversion region α and the photoelectric conversion region β. In the embodiment, adjustment is performed by applying different gains to the obtained image signals Iα and Iβ.
[0067]
Note that the schematic configuration of the camera in the second embodiment is the same as that described with reference to FIG. 1 in the first embodiment, and a description thereof will be omitted. FIG. 13 is a circuit configuration diagram of the image sensor 10 according to the second embodiment of the present invention. In FIG. 13, a two-column × two-row two-dimensional area sensor is shown for simplification of the drawing, but it is actually composed of several million pixels. In FIG. 13, the same reference numerals are assigned to the same components as those in FIG. 4, and description thereof is omitted.
[0068]
In the configuration shown in FIG. 13, there are two horizontal output systems, unlike FIG. 4, and 114L and 114H are differential amplifiers. Further, unlike the configuration shown in FIG. 4, the photoelectric conversion region α of each pixel is controlled by ΦTXαi, and the photoelectric conversion region β is controlled by ΦTXβi. That is, the wiring shown in FIG. Reference numeral 115 'denotes a horizontal scanning circuit 115' and a vertical scanning circuit 116 constitute the image sensor control circuit 21 shown in FIG.
[0069]
In FIG. 13, the left pixel (0th pixel) in the first line corresponds to the leftmost pixel shown in FIG. 17, and the right pixel (ith pixel) in the first line corresponds to the rightmost pixel in FIG. ing. Further, the optical axis of the taking lens 5 exists between the 0th pixel and the i-th pixel.
[0070]
In each pixel, the light output of the photoelectric conversion unit on the side close to the optical axis of the photographing lens 5, for example, the photoelectric conversion unit 101β0 of the 0th pixel and the photoelectric conversion unit 101αi of the i-th pixel is supplied to the low-gain differential amplifier 114L. It is comprised so that it may output. In each pixel, the photoelectric conversion unit far from the optical axis of the photographic lens 5, for example, the photoelectric conversion unit 101α0 of the 0th pixel and the photoelectric conversion unit 101βi of the i-th pixel are output by the high-gain differential amplifier 114H. It is comprised so that.
[0071]
Next, the operation of the image sensor 10 will be described using the timing chart of FIG. Since the camera 1 having the CMOS image sensor 10 of the present invention is configured so that an image taken by the image sensor 10 can be observed with the liquid crystal display element 9 at all times, accumulation control of a rolling shutter system is performed.
[0072]
FIG. 14 is a timing chart of the 0th line when focus detection is performed by the image sensor 10. When the focus state of the photographic lens 5 is detected, the correlation calculation of two images obtained from the respective outputs of the photoelectric conversion area α and the photoelectric conversion area β of each pixel is performed, and the photographic lens is calculated from the image shift amount of the two images. Although the five focus states are detected, the gains of the differential amplifiers 114L and 114H are set so that the outputs of the two images are substantially equal in the set focus detection region. Actually, out of the two photoelectric conversion regions in one pixel, the photoelectric sensor on the side farther from the optical axis of the photographing lens 5 than the gain given to the signal obtained from the photoelectric conversion region on the side closer to the optical axis of the photographing lens 5. Set so that the gain of the conversion area is high.
[0073]
First, among the photoelectric conversion regions divided into two of each pixel, the photoelectric charge is read out from, for example, the photoelectric conversion region α in the same dividing direction. The horizontal selection switch MOS transistor 106 is turned on by setting the control pulse ΦS0 to high, and the pixel portion of the 0th line is selected. Next, the control pulse ΦR0 is set to low, the reset of the FD unit 121 is stopped, the FD unit 121 is set in a floating state, and the gate and source of the source follower amplifier MOS transistor 105 are set to through. After a predetermined time, the control pulse ΦTNα is set to high. The dark voltage of the FD unit 121 is output to the storage capacitor 110α by the source follower operation.
[0074]
Next, in order to output the photoelectric conversion region α, the control switch ΦTXα0 is set to high, the transfer switch MOS transistor 103α is turned on, and the photogenerated carriers of the photoelectric conversion unit 101α are transferred to the FD unit 121. By transferring the charge from the photoelectric conversion unit 101α of the photodiode to the FD unit 121, the potential of the FD unit 121 changes according to light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD unit 121 is output to the storage capacitor 111α with the control pulse ΦTSα as high. At this time, the dark output and the light output of the photoelectric conversion region α are stored in the storage capacitors 110α and 111α, respectively. If the transfer switch MOS transistor 103α is closed by setting the control pulse ΦTXα0 to low, the accumulation of the photocharge is started in the photoelectric conversion region α, and the photocharge is accumulated until the photocharge is read again.
[0075]
Subsequently, the reading of the photoelectric charge in the photoelectric conversion region β is executed. The control pulse ΦS0 is set to high to turn on the horizontal selection switch MOS transistor 106 to select the pixel portion of the 0th line. Next, the control pulse ΦR0 is set to low, the reset of the FD unit 121 is stopped, the FD unit 121 is set in a floating state, and the source-follower amplifier MOS transistor 105 is turned through between the gate and the source. The dark voltage of the FD unit 121 is output to the storage capacitor 110β by the source follower operation.
[0076]
Next, in order to output the photoelectric conversion region β of each pixel of the 0th line, the control pulse ΦTXβ0 is set to high to turn on the transfer switch MOS transistor 103β, and the photoelectric charge of the photoelectric conversion unit 101β is transferred to the FD unit 121. The electric charge from the photoelectric conversion unit 101β of the photodiode is transferred to the FD unit 121, so that the potential of the FD unit 121 changes according to light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD unit 121 is output to the storage capacitor 111β with the control pulse ΦTSβ as high. At this time, the dark output and the light output of the photoelectric conversion region on the side far from the optical axis of the photographing lens of each pixel of the 0th line are stored in the storage capacitors 110β and 111β, respectively. If the transfer switch MOS transistor 103β is closed by setting the control pulse ΦTXβ0 to low, the accumulation of the photocharge is started in the photoelectric conversion region β, and the photocharge is accumulated until the photocharge is read again.
[0077]
The output from the image sensor is set to the control pulse ΦHC temporarily high to turn on the horizontal output line reset MOS transistor 113 to reset the horizontal output line, and to the horizontal transfer MOS transistor 112 of the horizontal scanning circuit 115 in the horizontal transfer period. It is output to the horizontal output line by the scanning timing signal.
[0078]
Here, the storage capacity from the photoelectric conversion region on the side close to the optical axis of the photographic lens 5, for example, the storage capacity 111β0 of the photoelectric conversion unit 101β0 of the 0th pixel and the storage capacity 111αi of the photoelectric conversion unit 101αi of the i-th pixel are low. A gain differential amplifier 114L is configured to output. On the other hand, the storage capacity from the photoelectric conversion region far from the optical axis of the photographic lens 5, for example, the storage capacity 111α0 of the photoelectric conversion unit 101α0 of the 0th pixel and the storage capacity 111βi of the photoelectric conversion unit 101βi of the i-th pixel are high gain. The differential amplifier 114H outputs the signal.
[0079]
Further, the horizontal scanning circuit 115 first generates a scanning timing signal so as to output the light output of the photoelectric conversion region α among the photoelectric conversion regions of each pixel. As a result, the storage capacitors from the storage capacitor 111α0 to the storage capacitor 111αi are output to the outside of the image sensor 10. Subsequently, the horizontal scanning circuit 115 generates a scanning timing signal so as to output the light output of the photoelectric conversion region β in the photoelectric conversion region of each pixel. As a result, the storage capacitors from the storage capacitor 111β0 to the storage capacitor 111βi are output to the outside of the image sensor 10. At this time, since the storage capacitors 110α and 111α or the storage capacitors 110β and 111β have a differential output VoutL or VoutH by the differential amplifier 114L or 114H, a signal with good S / N from which random noise and fixed pattern noise of the pixel are removed. Is obtained.
[0080]
The output from the image sensor 10 is shaped into a focus detection image signal by a CPU that performs focus detection. Since the output gain of the far side photoelectric conversion region is set higher than the far side photoelectric conversion region of the photographic lens 5, the output from each photoelectric conversion region is almost equal. As a result, the degree of correlation between the two image signals Iα and Iβ used for focus detection is increased, and it is possible to perform focus detection with high accuracy.
[0081]
When the CPU 20 accurately detects the focus state of the photographic lens 5 based on the focus detection signal output from the image sensor 10, the CPU 20 sets an electrical contact 26 provided between the camera body 1 and the photographic lens 5. The defocus information of the photographing lens 5 is transmitted to the lens CPU 50 through the lens CPU 50. The lens CPU 50 converts the defocus information received from the CPU 20 of the camera body 1 into a photographing lens driving amount and transmits the lens driving mechanism 51 to adjust the focus state of the photographing lens 5.
[0082]
Further, as is apparent from FIG. 16, the received light amount of the photoelectric conversion area closer to the optical axis of the photographic lens and the farther photoelectric conversion area depending on the open F value and the exit window of the photographic lens 5 attached to the camera body 1. The difference changes. FIG. 15 is a flowchart for setting the gain ratio (GL: GH) of the differential amplifiers 114L and 114H by the photographing lens attached to the camera body 1. Hereinafter, a description will be given with reference to the flowchart of FIG.
[0083]
The CPU 20 of the camera body 1 tries to communicate with the lens CPU 50 via the electrical contact 26 with the photographing lens 5 (step S201). If the photographing lens 5 is attached to the camera 1 and communication with the lens CPU 50 is possible (YES in step S201), the camera CPU 20 checks the type (ID) of the attached photographing lens 5 (step S202). When the type of the photographic lens mounted is confirmed, the CPU 20 confirms unique information such as the open F value and exit window information of the photographic lens stored in the memory circuit 22 (step S203). Further, the camera CPU 20 uses the information such as the open F value of the photographic lens 5 mounted, the position of the exit window, the diameter of the exit window, the position of the focus detection area on the image sensor 10 and the like to use the image sensor for focus detection. The gravity center position on the pupil of the photographing lens 5 of the received light beam received by each of the ten photoelectric conversion regions is calculated (step S204). Furthermore, the camera CPU 20 determines the angle formed between the straight line connecting the position of the center of gravity of the received light flux received by the photoelectric conversion regions α and β on the pupil of the photographing lens 5 and the photoelectric conversion regions α and β and the perpendicular of the image sensor 10. θα and θβ are calculated (step S204) (see FIG. 16). Here, the ratio of the amount of received light between the photoelectric conversion region α and the photoelectric conversion region β is approximately
COS4 (θα): COS4 (θβ)
[0084]
It becomes.
For example, when the photoelectric conversion region near the optical axis of the photographing lens is the photoelectric conversion region α and the photoelectric conversion region far from the optical axis of the photographing lens is the photoelectric conversion region β, the image sensor is represented by the timing chart shown in FIG. When 10 is controlled to accumulate, the CPU 20
GL / GH = COS4 (θβ) / COS4 (θα)
[0085]
Is set so as to satisfy (step S306).
When the gains of the differential amplifiers 114L and 114H of the image sensor 10 are controlled with the gain ratio set as described above, the output levels of the two focus detection image signals in a predetermined focus detection region are substantially equal. Focus detection using the two focus detection image signals provides a highly accurate result.
[0086]
Here, an example in which unique information such as the open F value of the photographing lens and exit window information is stored in the memory circuit 22 provided in the camera body 1 is shown. However, the system stores the information in the memory circuit associated with the lens CPU 50. You may memorize.
[0087]
Note that the timing chart and drive control when a normal image is captured in the second embodiment are the same as those described above with reference to FIG.
[0088]
[Other Embodiments]
In the first and second embodiments, the example in which the photoelectric conversion region in one pixel is divided in the horizontal direction and the accumulation time of each photoelectric conversion region is controlled has been shown, but the photoelectric conversion region in one pixel is In this case, it is desirable that the photoelectric conversion area near the photographing lens optical axis and the photoelectric conversion area far from the photographing lens can be controlled independently.
[0089]
In the first and second embodiments, the example in which the imaging device (image sensor) is arranged on the primary imaging surface of the photographing lens is shown. However, the imaging device (image sensor) is arranged on the secondary imaging surface of the secondary imaging optical system. Needless to say, this configuration is also effective.
[0090]
In the first and second embodiments, the case where the image sensor 10 is a CMOS image sensor has been described. However, the present invention is not limited to this, and may be a CCD image sensor, for example.
[0091]
It should be noted that the software configuration and the hardware configuration in the above embodiments can be appropriately replaced.
[0092]
In addition, you may make it this invention combine the above-mentioned each embodiment or those technical elements as needed.
[0093]
Further, the present invention is such that the configuration of the claims or the whole or a part of the configuration of the embodiment forms one device, but is combined with another device. Alternatively, it may be an element constituting the apparatus.
[0094]
The present invention is also applicable to various types of imaging devices such as video cameras, video still cameras, cameras with interchangeable photographing lenses, single-lens reflex cameras, lens shutter cameras, surveillance cameras, and devices applied to these imaging devices. The present invention can also be applied to a method, a medium such as a computer-readable storage medium, and elements constituting them.
[0095]
Another object of the present invention is to supply a storage medium (or recording medium) in which a program code of software that realizes the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (or CPU or CPU) of the system or apparatus. Needless to say, this can also be achieved by the MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included. Examples of the storage medium for storing the program code include a floppy disk, hard disk, ROM, RAM, magnetic tape, nonvolatile memory card, CD-ROM, CD-R, DVD, optical disk, magneto-optical disk, MO, and the like. Can be considered.
[0096]
Furthermore, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function is determined based on the instruction of the program code. It goes without saying that the CPU or the like provided in the expansion card or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.
[0097]
【The invention's effect】
As described above, according to the present invention, even when the amount of light incident on each photoelectric conversion area of the same pixel is different, the output of each photoelectric conversion area is controlled to be substantially the same, thereby improving the focus detection accuracy. It becomes possible to make it.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a camera according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of one pixel of the image sensor in the embodiment of the present invention.
FIG. 3 is a schematic plan view showing one line of the image sensor according to the first embodiment of the present invention.
FIG. 4 is a circuit configuration diagram of the image sensor according to the first embodiment of the present invention.
FIG. 5 is a drive timing chart of the image sensor at the time of focus detection in the first embodiment of the present invention.
FIG. 6 is a diagram illustrating an output of the image sensor according to the first embodiment of the present invention.
FIG. 7 is a diagram illustrating an output image of the image sensor according to the first embodiment of the present invention.
FIG. 8 is a diagram illustrating an output of the image sensor according to the first embodiment of the present invention.
FIG. 9 is a drive timing chart of the image sensor at the time of focus detection in the first embodiment of the present invention.
FIG. 10 is a flowchart of an accumulation time ratio determination process for focus detection in the first embodiment of the present invention.
FIG. 11 is a timing chart illustrating an example of image sensor driving during normal shooting according to the first embodiment of the present invention.
FIG. 12 is a timing chart showing another example of image sensor driving during normal shooting according to the first embodiment of the present invention.
FIG. 13 is a circuit configuration diagram of an image sensor according to a second embodiment of the present invention.
FIG. 14 is a drive timing chart of the image sensor at the time of focus detection according to the second embodiment of the present invention.
FIG. 15 is a flowchart of gain ratio determination processing for focus detection in the second embodiment of the present invention.
FIG. 16 is a diagram for explaining the principle of a conventional pupil division type focus detection method;
FIG. 17 is a schematic plan view showing one line of a conventional image sensor.
FIG. 18 is a diagram illustrating the output of a conventional image sensor.
FIG. 19 is a diagram illustrating an output image of an image sensor.
[Explanation of symbols]
1 Camera body
3 Eyepiece
5 Photography lens
9 Liquid crystal display elements
10 Image sensor
20 CPU
21 Image sensor control circuit
22 Memory circuit
23 Interface circuit
24 Image processing circuit
25 Liquid crystal display element drive circuit
26 Electrical contacts
50 lens CPU
51 Shooting lens drive mechanism
52 Aperture drive mechanism
53 Aperture device

Claims (8)

An imaging device that photoelectrically converts an optical image incident through a detachable photographic lens,
And pixels arranged plurality of two-dimensional area including the optical axes of the two have a photoelectric conversion means, connected imaging lens for receiving the light passing through the one microlens in each pixel,
When extracting the signal in adjusting the focus of the photographing lens, one of the two photoelectric converting means in said plurality of pixels in a two-dimensional area including the optical axis of the taking lens, the optical axis of the photographing lens the charge accumulation time of each photoelectric conversion means near side, so as to be shorter than the charge storage time of each of the photoelectric conversion means on the far side from the optical axis, each of the photoelectric conversion on the side close to the optical axis of the photographing lens It means through the first transfer pulse and said respective photoelectric conversion means from the optical axis on the far side of the taking lens imaging apparatus characterized by a control means for controlling independently the second transfer pulse. A straight line connecting the position of the center of gravity of the received light flux received by the two photoelectric conversion regions of each pixel on the pupil of the photographing lens, the photoelectric conversion region on the side close to the optical axis, and the photoelectric conversion region on the side far from the optical axis; Assuming that the angles formed with the perpendicular of the imaging device are θ1 and θ2, respectively, the accumulation period of the photoelectric conversion region near the optical axis is t1, and the accumulation time of the photoelectric conversion region far from the optical axis is t2, the control means ,
t1 / t2 = COS4 (θ1) / COS4 (θ2)
The imaging apparatus according to claim 1, wherein the charge accumulation time is set so as to satisfy the following. An imaging device that photoelectrically converts an optical image incident through a detachable photographic lens,
And pixels arranged plurality of two-dimensional area including the optical axes of the two have a photoelectric conversion means, connected imaging lens for receiving the light passing through the one microlens in each pixel,
Of the two photoelectric conversion means in the plurality of pixels in the two-dimensional area including the optical axis of the photographing lens, the respective photoelectric conversion means on the side close to the optical axis of the photographing lens are caused by the first transfer pulse. Each of the photoelectric conversion means on the side far from the optical axis of the photographic lens is controlled independently by a second transfer pulse;
A first gain is applied to a signal obtained from each of the photoelectric conversion means on the side close to the optical axis of the photographing lens among the photoelectric conversion means of the plurality of pixels in the two-dimensional area including the optical axis of the photographing lens. First amplification means;
A second amplification that applies a second gain larger than the first gain to a signal output from each photoelectric conversion means far from the optical axis of the photographing lens among the photoelectric conversion means of the plurality of pixels. Means,
The control device further controls the first and second gains according to a connected photographic lens. A straight line connecting the position of the center of gravity of the received light flux received by the two photoelectric conversion regions of each pixel on the pupil of the photographing lens, the photoelectric conversion region on the side close to the optical axis, and the photoelectric conversion region on the side far from the optical axis; Assuming that the angles formed with the perpendicular of the imaging device are θ1 and θ2, respectively, the first gain is G1, and the second gain is G2, the control means
G1 / G2 = COS4 (θ1) / COS4 (θ2)
The imaging apparatus according to claim 3, wherein the first and second gains are set so as to satisfy the following.   The imaging apparatus according to claim 1, wherein the control unit performs control based on a lens opening F value and exit window information of the connected photographing lens.   A camera equipped with the imaging apparatus according to claim 1. It is detachable from the taking lens,
Detecting means for detecting the attachment / detachment state of the photographing lens;
The camera equipped with the imaging device according to claim 3 or 4, further comprising: an acquisition unit configured to acquire information of the connected photographing lens. A focus detection unit that detects a focus state of the photographing lens based on signals output from two photoelectric conversion regions of each pixel of the imaging device;
The camera according to claim 7, wherein the control unit controls the first and second gains according to a position of a focus detection region on an imaging apparatus used by the focus detection unit.

Images