JP2015111252A - Imaging device, imaging device control method, program, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device capable of keeping AF accuracy even if a flicker is detected.SOLUTION: An imaging device includes: an imaging element including a plurality of pixels that can receive luminous fluxes passing through different regions of an exit pupil of a photographic optical system, respectively, and outputting a pair of image signals from the pixels; a first focus detection unit detecting a focus based on a phase difference between the paired image signals; an exposure control unit controlling a diaphragm stop of a diaphragm included in the photographic optical system; and a flicker detection unit detecting a flicker of illumination light. The exposure control unit exerts a flicker exposure control to set storage time of the imaging element to storage time for which the influence of the flicker is not reflected in an image picked up by the imaging element if the flicker detection unit detects the flicker of the illumination light and the first focus detection unit does not detect a focus. The exposure control unit does not exert the flicker exposure control if the flicker detection unit detects a flicker of the illumination light and the first focus detection unit detects a focus.

Description

  The present invention relates to an imaging apparatus capable of performing focus detection using an output from an imaging element.

  In recent years, an imaging apparatus typified by a single-lens reflex camera has greatly increased the weight for a shooting method while viewing an LV (live view) screen. Various methods have been proposed as an AF (autofocus) method of the image pickup apparatus on the LV screen, and one of them is an image pickup surface phase difference detection method.

  In the phase difference detection method, a light beam from a subject that has passed through different exit pupil regions in the imaging optical system is imaged on a pair of line sensors, and a phase difference between a pair of image signals obtained by the pair of line sensors is used. This is a method of calculating the defocus amount of the imaging optical system. As a phase difference detection using an image sensor, a configuration in which a plurality of photoelectric conversion elements are provided under the same microlens in an imaging pixel of the image sensor has been proposed. By receiving the light beams that have passed through different areas of the exit pupil area of the imaging optical system with a plurality of photoelectric conversion elements, it is possible to perform focus detection simultaneously with imaging.

  In Patent Document 1, each photodiode is configured to receive light from a different pupil plane of an imaging lens by dividing photodiodes collected by one microlens in one pixel. Has been. Thereby, the imaging plane phase difference detection method described above can be performed by comparing the outputs of two photodiodes. With this method, AF on the LV screen is realized.

  In addition, the quality of the through image is important in photographing while looking at the LV screen, and flicker removal and the like are performed in order to prevent deterioration of the display quality of the through image. Flicker means that when an image is taken under a light source whose luminance changes periodically according to a power supply frequency (50 Hz, 60 Hz, etc.), a horizontal stripe-like light-dark change occurs in an image signal for one frame. Specifically, when the power supply frequency is 50 Hz, the luminance of the light source changes with a period of 1/100 seconds, and when it is 60 Hz, the luminance of the light source changes with a period of 1/120 seconds.

  This light / dark change moves in the direction perpendicular to the exposure line of the image sensor as time passes. Such vertical periodic brightness is called flicker. A method of detecting flicker using an image sensor is proposed in Patent Document 2. In order to suppress flicker, a method is known in which imaging is performed with an accumulation time that is an integral multiple of the period of luminance change. That is, if the power supply frequency is 50 Hz, the accumulation time of the imaging apparatus is 1/50 seconds or 1/100 seconds, and if 60 Hz, the accumulation time is 1/60 seconds or 1/120 seconds. Hereinafter, 1 / (period of change in luminance of the light source) is referred to as a flicker frequency.

JP 2001-083407 A JP 2006-319831 A

  As described above, when the accumulation time is changed to (1 / flicker frequency) in order to remove flicker in a through image, the diaphragm may be narrowed more than usual in order to obtain an appropriate exposure.

  FIG. 6 is a normal program diagram, and FIG. 7 is a program diagram when 60 Hz flicker is removed. In the program diagram of FIG. 6, when ISO is 100, the accumulation time is shortened toward the high luminance side, and the diaphragm is narrowed down when the accumulation time reaches the shortest time.

  On the other hand, in the program diagram when flicker is removed in FIG. 7, it can be seen that 1/120, 1/60, and 1/30 second, which are integral multiples of the flicker frequency, are used. When the ISO is 100, the aperture is gradually reduced by one step toward the high luminance side, and when it reaches the first step, the accumulation time is increased by one step to 1/60 seconds, so that 1/30 seconds to 1/60 seconds. Transition up to seconds. The same applies to 1/60 seconds to 1/120 seconds. In the case of EV6, the accumulation time is 1/500 seconds (FIG. 6) in the normal program diagram, whereas the accumulation time is 1/120 seconds (FIG. 7) in the program diagram when flicker is removed. It can be seen that it is.

  At this time, flicker is removed from the live view image, but the overexposure is overexposed. Here, the aperture value is F2 in the normal program diagram, whereas the aperture value is F4 in the program diagram at the time of flicker removal. As the aperture value of AF increases, the length of the line becomes shorter and the accuracy varies. For this reason, when the flicker is removed as described above, if AF is performed with the aperture set smaller than that at the time of shooting, there is a high possibility that a focus shift will occur.

  The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide an imaging apparatus capable of maintaining AF accuracy even when flicker is detected.

  An imaging apparatus according to the present invention includes a plurality of pixels each capable of receiving a light beam that has passed through different areas of an exit pupil of a photographing optical system, and an imaging element that outputs a pair of image signals from the plurality of pixels, and the pair of pairs. First focus detection means for performing focus detection based on the phase difference of the image signals of the image sensor, exposure control means for controlling the storage time of the image sensor, the aperture value included in the photographing optical system, and flicker of illumination light Flicker detection means for detecting the flicker of the illumination light is detected by the flicker detection means, and when the focus detection by the first focus detection means is not performed, the exposure control means The flicker exposure control is performed to set the accumulation time of the image sensor to an accumulation time in which the influence of the flicker does not appear in the image captured by the image sensor. The flicker of illumination light is detected, if the focus detection is performed by the first focus detection unit is characterized in that it does not perform exposure control for the flicker.

  According to the present invention, it is possible to provide an imaging apparatus that can maintain AF accuracy even when flicker is detected.

1 is a block diagram showing a schematic configuration of an imaging apparatus according to a first embodiment of the present invention. The figure which shows the pixel structure of the imaging surface phase difference AF in embodiment of this invention. The figure which showed the flow of operation | movement of the imaging device at the time of LV starting in 1st Embodiment. 3 is a flowchart illustrating an overall operation of the imaging apparatus according to the first embodiment. The flowchart which showed the flow of the operation | movement at the time of AF in 1st Embodiment. The program chart at the normal time in the embodiment of the present invention. The program diagram at the time of flicker (60 Hz) removal in the embodiment of the present invention. The flowchart which showed the flow of the operation | movement at the time of AF in 2nd Embodiment. 9 is a flowchart showing a flow of continuous shooting operation in the third embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the dimensions, shapes, relative arrangements, and the like of the components exemplified in the following embodiments should be changed as appropriate according to the configuration of the apparatus to which the present invention is applied and various conditions. However, the present invention is not limited to these examples.

(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of an imaging apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the imaging apparatus of the present embodiment includes a lens unit 10 and a camera 20, and includes a lens control unit 106 that controls the overall operation of the lens unit, and a camera that controls the overall operation of the camera. The control unit 212 communicates information.

  First, the configuration of the lens unit 10 will be described. The lens unit 10 includes a fixed lens 101, an aperture 102, a focus lens 103, an aperture drive unit 104, a focus lens drive unit 105, a lens control unit 106 that controls lens drive, and a lens operation unit 107. The photographing optical system includes a fixed lens 101 to a focus lens 103, 101 denotes a fixed first group lens, 102 denotes a diaphragm, and 103 denotes a focus lens.

  The diaphragm 102 is driven by the diaphragm controller 104 and controls the amount of light incident on the image sensor 201 described later. The focus lens 103 is driven in the optical axis direction by the focus lens driving unit 105 and adjusts the focus of the optical image formed on the image sensor 201. The aperture driving unit 104 and the focus lens driving unit 105 are controlled by the lens control unit 106 to determine the aperture amount of the aperture 102 and the position of the focus lens 103.

  When there is a user operation on the lens operation unit 107, the lens control unit 106 performs control according to the user operation. The lens control unit 106 controls the aperture driving unit 104 and the focus lens driving unit 105 in accordance with a control command / control information received from a camera control unit 212 described later, and transmits lens control information to the camera control unit 212. To do.

  Next, the configuration of the camera 20 will be described. The camera 20 is configured to acquire an imaging signal from a light beam that has passed through the imaging optical system of the lens unit 10. The image sensor 201 is an image sensor composed of a CCD or CMOS sensor. The light flux that has passed through the imaging optical system of the lens is imaged on the light receiving surface of the image sensor 201 and converted into a signal charge corresponding to the amount of incident light by a photodiode. The incident time (exposure time) of the light beam at this time is controlled by the camera control unit 212.

  The signal charge accumulated in each photodiode is sequentially read out from the image sensor 201 as a voltage signal corresponding to the signal charge based on a drive pulse given from the timing generator 215 in accordance with a command from the camera control unit 212.

  The imaging element 201 holds two photodiodes (photoelectric conversion elements) capable of receiving a light beam in one pixel in order to perform imaging plane phase difference AF (focus detection). In the case of an image sensor that does not correspond to the imaging surface phase difference AF, for example, the pixel configuration has a Bayer array as shown in FIG. On the other hand, the imaging device 201 of the present embodiment holds a plurality of (two in the present embodiment) photodiodes in one pixel as shown in FIG. 2B in order to perform imaging plane phase difference AF. Yes. That is, a plurality of photodiodes are provided under one microlens. Two signals for imaging and AF can be acquired by separating the luminous flux with a microlens and receiving light that has passed through different areas of the exit pupil area with two photodiodes. A signal (A + B) obtained by adding the signals of the two photodiodes is an imaging signal, and the signals (A, B) of the individual photodiodes are two image signals (a pair of image signals) for AF. Here, the configuration is not limited to reading each of the two image signals. For example, in consideration of a processing load, the added signal (A + B) and one image signal (for example, A) are read, and the other image signal is calculated from the difference. (For example, B) may be acquired. An AF signal processing unit 204 (to be described later) performs a correlation operation on the two image signals to calculate an image shift amount and various types of reliability information.

  In the present embodiment, the configuration of the imaging device having two photodiodes in one pixel is used, but the number of photodiodes is not limited to two and may be more. In addition, the configuration of the imaging device corresponding to the imaging surface phase difference AF is not limited to the configuration in which a plurality of photodiodes are provided in one pixel as in the present embodiment, and discrete focus detection pixels are provided in the imaging device. It may be a configuration.

  A signal read from the image sensor 201 is input to the CDS / AGC / AD converter 202, and correlated double sampling for removing reset noise, gain adjustment, and signal digitization are performed. The CDS / AGC / AD converter 202 outputs the imaging signal to the image input controller 203 and the imaging surface phase difference AF signal to the AF signal processing unit 204.

  The image input controller 203 stores the imaging signal output from the CDS / AGC / AD converter 202 in the SDRAM 209. The imaging signal stored in the SDRAM 209 is displayed on the display unit 206 by the display control unit 205 via the bus 21. In the mode for recording the imaging signal, the recording medium control unit 207 records the image on the recording medium 208.

  Here, the imaging signal stored in the SDRAM 209 is also sent to the camera control unit 212 via the bus 21. Using this imaging signal, the camera control unit 212 detects the current flicker frequency. The AF signal processing unit 204 performs correlation calculation based on the two image signals for AF output from the CDS / AGC / AD converter 202, and calculates an image shift amount. The calculated image shift amount is output to the camera control unit 212. Further, the camera control unit 212 notifies the AF signal processing unit 204 of a change in the setting for calculating these based on the acquired image shift amount.

  In the present embodiment, a total of three signals, that is, an imaging signal and two AF image signals are extracted from the imaging element 201, but the present invention is not limited to this method. Considering the load on the image sensor 201, for example, taking out a total of two of the image signal and the AF image signal, and generating another AF image signal by taking the difference between the image signal and the AF signal Anyway.

  The camera control unit 212 can determine the current luminance from the imaging signal. The camera control unit 212 also performs exposure determination using the luminance to determine the image accumulation time, aperture size, ISO sensitivity, and the like. In this exposure determination, not only exposure as a still image but also exposure determination for a through image for LV (live view) display is performed.

  The camera control unit 212 performs control by exchanging information with the entire block in the camera 20. In response to input from the camera operation unit 214 as well as processing within the camera 20, the user has performed operations such as power ON / OFF, setting change, recording start, AF control start, and recorded video confirmation. Perform various camera functions.

  Further, as described above, the camera control unit 212 exchanges information with the lens control unit 106 in the lens unit 10, sends a control command / control information to the lens, and acquires information in the lens. The ROM 210 connected via the bus 21 stores a control program executed by the camera control unit 212 and various data necessary for control. The flash ROM 211 relates to the operation of the camera 20 such as user setting information. Various setting information and the like are stored.

  Next, the operation of the imaging apparatus configured as described above will be described. First, the overall flow at the time of shooting in this embodiment will be described with reference to the flowchart of FIG.

  When an instruction for a shooting preparation operation is received from the camera operation member 214 (S401), that is, when the SW1 of the release switch is turned on, the camera control unit 212 first performs an AF (autofocus) operation (S402). The AF operation will be described later. Since the normal LV (live view) display is restored at the end of AF, the normal LV operation is performed.

  As a normal LV operation, first, imaging for a through image is performed (S403). Next, the camera control unit 212 performs photometry using the image pickup signal (S404), and controls the display unit 206 to display an image obtained from the image pickup signal in S405.

  Using the photometric value obtained by the photometry in S404, the camera control unit 212 first determines the exposure of the next through image (S406). Next, using the photometric value obtained by the photometry in S404, the camera control unit 212 determines the exposure for still image shooting (S407).

  If an instruction for a photographing operation is received by the camera operating member 214 (S408), that is, if the release switch SW2 is turned on, the process proceeds to photographing. Then, the camera control unit 212 performs a shooting operation and a shot image recording process with the exposure determined in step S407. On the other hand, if an instruction for photographing operation is not received in S408, the process returns to S403 to continue the LV display.

  Next, the flow at the time of starting LV (live view) will be described with reference to FIG.

  First, the current flicker frequency of the illumination light is detected by the camera control unit 212 using the imaging signal read from the imaging device 201 when the LV screen is activated (S101). If no flicker is detected (No in S102), the process proceeds to S103, and the exposure according to the luminance is determined using the normal program diagram of FIG. 6 (exposure control). The program diagram here is for a through image used for LV display. In the through image used in the LV display state (live view display state), the frame rate is determined by the update timing or the read timing by the drive pulse given from the timing generator 215, and there is a limitation on the accumulation time. The slowest frame rate here is 30 fps, and the slowest second of the accumulation time is also 1/30 seconds.

  If flicker exists (Yes in S102), the program diagram is changed according to the flicker frequency (S104), and the exposure is determined according to the luminance. If the flicker is 50 Hz, a program diagram for removing 50 Hz flicker is used at S105 (flicker exposure control). If the flicker is 60 Hz, a program line for removing 60 Hz flicker at S106. Use the figure. The program diagram at the time of flicker detection shown in FIG. 7 is that when the flicker is 60 Hz.

  As shown in FIG. 7, the accumulation time is controlled by an integer multiple of 1/120 second which is (1 / flicker frequency). At this time, the exposure is controlled by correcting the exposure error caused by the accumulation time being controlled by an integral multiple of 1/120 seconds with the stop so as to obtain an appropriate exposure.

  In step S107, the camera control unit 212 sets a frame rate. In this embodiment, it is 30 Hz. If the setting so far is performed, a through image is captured in S108, and photometry is performed based on the captured signal in S109. Then, the camera control unit 212 displays a through image in S110 and determines the next exposure using the value measured in S109 earlier (S111). The exposure here follows the program diagram determined earlier. After that, LV display is performed by repeating S108 to S111.

  Next, the flow of the AF (autofocus) operation of this embodiment executed when SW1 is turned on during LV (live view) will be described with reference to FIG. The AF operation here corresponds to S402 in FIG. When an instruction to start AF control (ON of SW1) is received from the camera operation unit 214, it is first determined whether the program diagram at the time of detecting flicker is used or the program diagram at normal time is used (S202). .

  If the program diagram at the time of flicker detection is not used (No in S202), the AF operation is started in S203. If the program diagram at the time of flicker detection is used (Yes in S202), the camera control unit 212 changes in S204 to use the normal program diagram and determines the exposure in S205. This is because if the AF is performed in a state where the program diagram at the time of flicker detection is used, the aperture is narrowed down in a bright scene, which causes a decrease in AF accuracy.

  Here, when the exposure is returned to the normal program diagram, flickering of the display due to flicker occurs. In order to suppress the flickering of the display, the frame rate is changed (frame rate control). When the accumulation time is not set to an integral multiple of (1 / flicker frequency) seconds, stripes are generated in the through image. In addition, display flickering occurs when the stripes move.

  Here, by adjusting the frame rate to the flicker frequency, although the fringe is generated in the through image, the fringe can be fixed and the display flicker is eliminated. For example, the frame rate is changed to 50 fps at 50 Hz, and is changed to 60 fps at 60 Hz. In this way, display flicker due to flicker can be suppressed.

  The camera control unit 212 determines the flicker frequency in S206 as described above, and changes the frame rate in accordance with the flicker frequency as in S207 and S208. When the program diagram is returned to the normal diagram and the change of the frame rate is completed, AF is started in S209. When AF is completed, if a program diagram for flicker removal is originally used, the program diagram is restored (S210), the frame rate is also restored (S211), and the normal LV is restored.

  As described above, according to the present embodiment, when flicker is detected during the AF operation, the accuracy of AF can be guaranteed even under a flicker light source by changing to a normal program diagram. it can. At that time, flickering of the through image can be suppressed by changing the frame rate according to the flicker frequency.

  Note that the change of the frame rate in the above embodiment is for flicker reduction, but the frame rate may be changed according to other requirements (such as higher AF speed). Also, the program diagram may be changed according to other requirements.

(Second Embodiment)
In the AF method in LV (live view), a contrast value is calculated by extracting a specific frequency component from the image pickup signal, and the peak is detected by acquiring the contrast value while moving the focus lens to focus. There is also a contrast detection method for matching. In the imaging apparatus having the above-described configuration, it is assumed that the contrast detection method described above can be realized by calculating a contrast value from the imaging signal obtained by the imaging element 201 by the camera control unit 212.

  In the contrast detection method, since the contrast value of the imaging signal is used, the fringe fringes have a great influence on the contrast value, and the focus accuracy is significantly reduced. In this configuration, it is assumed that the imaging surface phase difference method and the contrast detection method can be switched under several conditions such as the type of lens unit and the subject.

  Hereinafter, the second embodiment will be described. When LV (live view) is activated, flicker detection is performed in the same manner as in the first embodiment according to FIG. 3. If flicker is detected, a program diagram for flicker removal is used, and if not detected, a normal program diagram is used. Is used.

  Next, the flow at the time of AF executed when SW1 is turned on during LV will be described with reference to FIG. When an instruction to start AF control is received from the camera operation unit 214 (ON of SW1), it is first determined whether to use the imaging surface phase difference method or the contrast detection method (S301).

  If the imaging surface phase difference method is used, it is determined in S303 whether the program diagram at the time of flicker detection is currently used or the program diagram at the normal time is used as in S202 of FIG. The program diagram is switched and the AF operation is performed.

  If the contrast detection method is used, the flicker fringes significantly reduce the focus accuracy. Therefore, even if the program diagram is for flicker removal, the AF operation is performed without returning to the normal program diagram. That is, if the contrast detection method is used, AF is started without changing the diagram or the frame rate at the start of AF (S302).

  By performing the control as described above, AF can be performed while suppressing a reduction in focus accuracy even when a contrast detection method is used together under a flicker light source.

(Third embodiment)
In continuous shooting while AF (autofocus) is performed, captured images are sequentially displayed, while AF may be performed using an image signal that is not used for display. At this time, since imaging for AF is not used for display, there is no need to worry about flicker. Therefore, a normal program diagram can be used without using a program diagram for removing flicker in imaging for AF during shooting during continuous shooting.

  The flow of continuous shooting operation in such a case will be described with reference to the flowchart of FIG. First, after the still image shooting (S501) is completed, the camera control unit 212 determines whether a continuous shooting instruction is received from the camera operation member 214 (S502). If no continuous shooting instruction has been received, the continuous shooting is terminated and the normal LV (live view) is restored. If a continuous shooting instruction has been received, the camera control unit 212 performs photometry (S503) using an image pickup signal for still image shooting. Thereafter, the still image taken in S501 is displayed on the display unit 206 (S504).

  Next, the camera control unit 212 determines an exposure for imaging for acquiring a signal for imaging plane phase difference AF using the photometric value measured in S503 (S505). Here, the exposure in S505 is determined using a normal program diagram without using a program diagram for flicker removal. The camera control unit 212 performs AF imaging using the exposure determined in S505, and acquires an imaging plane phase difference AF signal (S506).

  The imaging surface phase difference signal acquired in S506 is calculated by the AF signal processing unit 204 to calculate a phase shift amount (S507). The camera control unit 212 performs AF by instructing the lens control unit 106 to drive the focus lens 103 using the shift amount (S508). When AF ends, the process returns to S501 and the still image shooting is performed again. As described above, continuous shooting while performing AF is realized.

  According to the above method, the accuracy as AF can be guaranteed without causing the flicker effect on the LV image even under a flicker light source during continuous shooting.

  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.

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

10: Lens unit, 20: Camera, 101: Fixed lens, 102: Aperture, 103: Focus lens, 104: Aperture drive unit, 105: Focus lens drive unit, 106 lens control unit, 201: Image sensor, 212: Camera control Part

Claims (9)

An image sensor that includes a plurality of pixels each capable of receiving light beams that have passed through different areas of the exit pupil of the imaging optical system, and that outputs a pair of image signals from the plurality of pixels;
First focus detection means for performing focus detection based on a phase difference between the pair of image signals;
An exposure control means for controlling an accumulation time of the image sensor and an aperture value included in the photographing optical system;
Flicker detection means for detecting flicker of illumination light,
When the flicker of the illumination light is detected by the flicker detection unit and the focus detection by the first focus detection unit is not performed, the exposure control unit determines the accumulation time of the image sensor as the influence of the flicker. Performs flicker exposure control that is set to an accumulation time that does not appear in the image picked up by the image sensor, the flicker of the illumination light is detected by the flicker detection means, and focus detection by the first focus detection means is performed. In the case where it is performed, the flicker exposure control is not performed.   2. The imaging apparatus according to claim 1, wherein the phase difference type focus detection by the first focus detection unit is performed in a state in which an image captured by the imaging element is displayed in a live view.   In the live view display, an image signal subjected to the flicker exposure control is displayed, and focus detection by the first focus detection unit is acquired at a time during imaging of the image signal used for the live view display. The imaging apparatus according to claim 2, wherein the imaging apparatus is performed based on a signal that does not perform the flicker exposure control.   A frame rate control unit for controlling a frame rate in the live view display is further provided, and when the exposure control unit does not perform the flicker exposure control, the frame rate is adjusted to a flicker frequency. Item 3. The imaging device according to Item 2.   In the flicker exposure control, the accumulation time of the image sensor is set to an integral multiple of (1 / flicker frequency) seconds, and the accumulation time is set to an integral multiple of (1 / flicker frequency) seconds. The imaging apparatus according to claim 1, wherein a generated exposure error is corrected by the aperture value.   A second focus detection unit that performs focus detection based on a contrast of an image obtained from the image sensor; and a switching unit that switches between the focus detection based on the phase difference method and the focus detection based on the contrast, and 6. When performing focus detection by a second focus detection unit, the exposure control unit performs the flicker exposure control when flicker of the illumination light is detected. The imaging device according to any one of the above. A method of controlling an imaging apparatus comprising a plurality of pixels each capable of receiving a light beam that has passed through different areas of an exit pupil of an imaging optical system, and comprising an imaging element that outputs a pair of image signals from the plurality of pixels,
A first focus detection step of performing focus detection based on a phase difference between the pair of image signals;
An exposure control step for controlling the accumulation time of the image sensor and the aperture value of the lens;
A flicker detection process for detecting flicker of illumination light,
In the exposure control step, when the flicker of the illumination light is detected by the flicker detection step and focus detection is not performed by the first focus detection step, the accumulation time of the image sensor is set as the influence of the flicker. Performs an exposure control for flicker that is set to an accumulation time that does not appear in the image captured by the image sensor, and the flicker of the illumination light is detected by the flicker detection step, and the focus detection by the first focus detection step is performed. If performed, the flicker exposure control is not performed.   The program for making a computer perform each process of the control method of Claim 7.   A computer-readable storage medium storing a program for causing a computer to execute each step of the control method according to claim 7.

Images