Imaging apparatus and control method

Abstract

To improve exposure followability when an imaging interval is long in continuous imaging or the like under a flicker environment.SOLUTION: An imaging apparatus 100 performs display imaging for acquiring a display image between first imaging for acquiring a recording image and a following second imaging. The imaging apparatus includes photometric means 107 for performing photometry using an image and control means 104 for performing exposure control according to the result of the photometry. The control means performs the exposure control in the second imaging when a flicker is included in light made incident on the imaging apparatus, according to the result of the photometry using the recording image acquired by the first imaging, when an interval between the first imaging and the second imaging is shorter than a predetermined time and performs the exposure control in the second imaging when the flicker is included in the light made incident on the imaging apparatus, according to the result of the photometry using the display image, when the interval is longer than the predetermined time.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an imaging device such as a digital camera. [Background technology]

[0002] Artificial light sources such as fluorescent lights are known to cause flicker, in which the amount of light changes periodically due to the influence of commercial power supply frequencies. When a subject is continuously captured under such a flickering light source with a shutter speed (or charge accumulation time of the image sensor) shorter than the period of change in the amount of light caused by the flickering, uneven brightness and color may occur among the multiple still images obtained by the continuous capture. Furthermore, when a moving image captured under a flickering light source is displayed on a monitor as a live view image, stripes due to the influence of the flicker may appear in the image or the brightness of the entire image may change depending on the charge accumulation time and frame rate. Therefore, even if a photometric value is calculated from the live view image generated between consecutive captures, the effect of the stripes makes it impossible to obtain an accurate photometric value.

[0003] Patent Document 1 discloses a method for obtaining accurate photometric values ​​by adjusting the charge accumulation timing during still image capture in accordance with changes in the light intensity caused by flicker to obtain a stripe-free still image and then calculating the photometric value using the still image. The same patent document also discloses a method for reducing the effects of flicker and obtaining accurate photometric values ​​from live view images by setting the charge accumulation time during live view image capture to an integer multiple of the cycle of changes in the light intensity caused by flicker. The same patent document also discloses that photometric values ​​are always obtained from still images during continuous image capture. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-010317 Summary of the Invention [Problem to be solved by the invention]

[0005] In continuous image capture, if an accurate photometric value is to be obtained from a live view image, the charge accumulation time for generating the live view image is extended, resulting in a longer interval between still image captures. Therefore, when the continuous image capture speed is fast, it is desirable to obtain an accurate photometric value from a still image. However, in such continuous image capture, the imaging parameters for the next still image capture are determined based on the photometric value calculated using the still image acquired in the previous still image capture. For this reason, the longer the interval between still image captures (the slower the continuous image capture speed), the worse the exposure tracking performance.

[0006] The present invention provides an imaging device and a control method thereof that are capable of improving exposure tracking when the imaging interval is long during continuous imaging in a flickering environment. [Means for solving the problem]

[0007] An imaging device according to one aspect of the present invention is an imaging device that performs display imaging to obtain an image for display between a first imaging to obtain an image for recording and a subsequent second imaging, and includes a photometry means that performs photometry using the image, a detection means that detects flicker, and a control means that performs exposure control in accordance with the results of the photometry, and is characterized in that the control means performs exposure control for the second imaging when the detection means detects flicker in such a way that when the interval between the first imaging and the second imaging is shorter than the flicker period, the control means performs exposure control in accordance with the results of photometry using the image for recording obtained in the first imaging, and when the interval is equal to or longer than the flicker period, the control means performs exposure control in accordance with the results of photometry using the image for display.

[0008] Another aspect of the present invention provides a control method for an imaging device that performs a display image capture to capture an image for display between a first image capture to capture an image for recording and a subsequent second image capture, and performs photometry using the image and exposure control in accordance with the result of the photometry, the control method including a detection step of detecting flicker, a photometry step of performing photometry using the captured image, and an exposure control step of controlling exposure in accordance with the result of the photometry step, wherein if flicker is detected in the detection step, the exposure control step performs exposure control in the second image capture in accordance with the result of photometry using the image for recording captured in the first image capture when the interval between the first and second image captures is shorter than the flicker period, and in accordance with the result of photometry using the image for display when the interval is equal to or longer than the flicker period. Note that a program that causes a computer of the imaging device to execute processing in accordance with the above control method also constitutes another aspect of the present invention. [Effects of the Invention]

[0009] The present invention can improve exposure tracking when the interval between captures for recording is long during continuous capture under a flickering environment. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of an imaging system according to a first embodiment. [Figure 2] FIG. 1 is a block diagram showing the electrical configuration of an imaging system according to a first embodiment. [Figure 3] 10 is a flowchart showing an imaging process for detecting flicker during live view display in the first embodiment. [Figure 4] 4 is a flowchart showing a continuous image capturing process in the first embodiment. [Figure 5] 6 is a timing chart showing the continuous image capturing process (when the image capturing interval time is less than a predetermined value) in the first embodiment. [Figure 6] 6 is a timing chart showing the continuous image capturing process (when the image capturing interval time is equal to or greater than a predetermined value) in the first embodiment. [Figure 7]10 is a flowchart showing a continuous image capturing process in the second embodiment. [Figure 8] 10 is a timing chart showing the continuous image capturing process (when the image capturing interval time is equal to or greater than a predetermined value) in the second embodiment. [Figure 9] 11 is a flowchart showing a continuous image capturing process in the third embodiment. [Figure 10] 10 is a flowchart showing a continuous image capturing process in the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Example]

[0012] Fig. 1 shows a schematic configuration of an imaging system according to a first embodiment of the present invention. The imaging system includes an imaging device (hereinafter referred to as a camera body) 100, an imaging lens 200, and an external strobe 300. Fig. 2 shows the electrical configuration of the imaging system.

[0013] The imaging lens 200 is detachable from the camera body 100 and includes an optical system including a lens group 201 and an aperture 202, and a lens control unit (LPU) 203. The optical system forms an image of a subject by focusing light from a subject (not shown). The LPU 203 communicates with the camera body 100 and controls the positions of the zoom lens and focus lens in the lens group 201 and the aperture diameter of the aperture 202 via a lens driving unit 204 and an aperture driving unit 205.

[0014] In the camera body 100, the image sensor 101 is a charge-storage solid-state image sensor such as a CCD sensor or CMOS sensor that includes an infrared cut filter, a low-pass filter, etc., and captures (photoelectrically converts) an image of a subject formed by the imaging lens 200. A live view display is performed by displaying a moving image (live view image) as a display image generated from the imaging signal from the image sensor 101 on the display unit 103. The image generated from the imaging signal from the image sensor 101 is also used as a still image for recording or for detecting flicker, which will be described later.

[0015] The shutter 102 is disposed on the optical path of light from the imaging lens 200, closer to the subject (front) than the imaging element 101. The shutter 102 has blade members (curtains), which block light from the imaging lens 200 when the blade members are deployed and closed, and allow light from the imaging lens 200 to form an image on the imaging element 101 when the blade members are folded and open. The amount of light incident on the imaging element 101 can be controlled by controlling the travel speed of the shutter 102. The brightness of an image generated from an imaging signal can be changed according to exposure conditions including the travel speed of the shutter 102 and the exposure time (charge accumulation time) of the imaging element 101. Note that an electronic shutter that performs accumulation control in the imaging element 101 may have the same function as the shutter 102.

[0016] The display unit (hereinafter simply referred to as the display) 103 is a display means configured with a TFT LCD (thin film transistor liquid crystal display) or the like. The display 103 displays a live view image, exposure conditions at the time of image capture, and other information regarding image capture parameters. The display 103 is equipped with a touch panel that can be operated by touching the screen. Various types of touch panels can be used, such as a capacitance type.

[0017] A system control unit (CPU) 104 is a control means that controls not only the camera body 100 but also the entire imaging system. The processing that the CPU 104 executes according to a program as a computer will be described later.

[0018] The shutter control unit 105 controls the shutter speed by controlling the opening and closing operation of the shutter 102 based on the time specified by the CPU 104. The signal processing unit 106 generates image data (live view images for display and still images and moving images for recording) by performing various image processing on the imaging signal from the imaging element 101. The signal processing unit 106 performs image interpolation, resizing, color conversion, and white balance (WB) processing on the image data.

[0019] The recording unit 112 records the still images and moving images for recording generated by the signal processing unit 106 onto a recording medium such as a semiconductor memory.

[0020] The image capture mode selection unit 109 selects an image capture mode that can be set on the camera body 100 in response to a user operation. The image capture modes are modes that differ in the method of setting exposure-related elements (exposure control values), and include aperture value (Av) priority mode, shutter speed (Tv) priority mode, etc. The CPU 104 controls the camera body 100 in the image capture mode selected by the image capture mode selection unit 109.

[0021] The image capture instruction unit 110 instructs the CPU 104 to perform an image capture preparation operation in response to a half-press operation by the user, and instructs the CPU 104 to perform an image capture operation in response to a full-press operation.

[0022] The imaging setting input unit 111 accepts inputs from the user for setting various modes and functions in the camera body 100. The imaging setting input unit 111 includes input members such as a rotary dial, a cross key, a confirmation button, and a reset button. Modes and functions that can be set through the imaging setting input unit 111 include a metering mode, an imaging mode, a continuous imaging function, a flicker-free imaging function (described later), a live view display, and a light-emitting imaging function. The modes and functions set through the imaging setting input unit 111 are displayed on the display 103 as a graphical user interface (GUI) or icons.

[0023] The subject brightness determination unit 107, which serves as photometry means, determines (detects) a brightness value representing the brightness of the subject from the image data output from the signal processing unit 106. That is, photometry is performed using the image data. Specifically, the subject brightness determination unit 107 divides each unit image (frame image) from the acquired image data into a plurality of blocks and calculates an average brightness value for each block. It then integrates the average brightness value for each block to obtain a representative brightness value. In the following description, this representative brightness value is used as the brightness value of the subject, and this brightness value is used as the photometry result (photometric information or brightness information) for various controls and processes. Note that the method for detecting the brightness value is not limited to this, and various methods can be adopted.

[0024] The CPU 104 as a control means calculates exposure control values ​​(shutter speed, aperture value, ISO sensitivity, etc.) based on the brightness value detected by the subject brightness determination unit 107 and the imaging mode selected by the imaging mode selection unit 109, etc.

[0025] Focal length determination unit 108 calculates information for determining whether the position of the focus lens included in imaging lens 200 is an in-focus position where a focused state on the subject can be obtained, based on image data from signal processing unit 106. If the current position of the focus lens is an out-of-focus position based on this calculated information, CPU 104 communicates with LPU 203 to control the position of focus lens 200. CPU 104 can also control the position of the focus lens in response to a user operation input.

[0026] The external strobe 300 serving as the illumination means is an external light-emitting device that can be attached to and detached from the camera body 100, and has a light-emitting unit (not shown). The external strobe control unit (SPU) 301 in the camera body 100 determines whether or not the external strobe 300 needs to emit light (to illuminate the subject) based on a brightness value from the CPU 104, and controls the light emission of the light-emitting unit if illumination is required. The SPU 301 can also control the light emission of the light-emitting unit in response to user operations. Note that the built-in strobe 114 built into the camera body 100 may also be used as the illumination means. (Flicker detection and flicker-free imaging functions) Next, the imaging process performed in camera body 100 from flicker detection during imaging for live view display to still image imaging will be described.

[0027] The flowchart in Fig. 3 shows the continuous image capture process executed by the CPU 104 as a computer in accordance with a program. Here, as an example, a case will be described in which, with the flickerless image capture function turned on (enabled) beforehand, image capture for live view display is started in response to the power switch (not shown) of the camera body 100 being turned on, and then continuous image capture is started. Note that the continuous image capture referred to here refers to image capture in a so-called continuous shooting mode, in which multiple image captures for recording are performed consecutively by continuing to fully press the image capture instruction unit 110.

[0028] When the power switch of the camera body 100 is turned on, in step S101, the CPU 104 acquires image data generated from the imaging signal of the image sensor 101 and performs photometry using the image data. This initial photometry is performed to optimize the exposure conditions (exposure time, aperture value, ISO sensitivity) when imaging a subject before starting processing related to imaging for live view display and flicker detection.

[0029] Next, in step S102, CPU 104 as a detection means detects flicker contained in light incident on camera body 100 (image sensor 101) from imaging lens 200 (i.e., a flicker light source illuminating the subject). In detecting flicker, for example, image sensor 101 stores and reads out electric charges at 600 fps (a cycle of approximately 1.667 ms) 12 times in succession, and calculates the cycle of the change in light intensity of the flicker (hereinafter referred to as the flicker cycle) from the photometric value obtained as the output of image data. Explanation of how the flicker cycle is calculated will be omitted. If flicker is detected, CPU 104 performs the process of step S104, and if flicker is not detected, it performs the process of step S114.

[0030] Note that detecting flicker is not necessarily required; for example, if the user is aware of the presence of a flickering light source and the flicker cycle and sets the camera body 100 to capture images in a flickering environment, the process may proceed to step S104; if no such settings have been made, the process may proceed to step S114.

[0031] In step S104, the CPU 104 sets a charge accumulation time for the image sensor 101 that reduces the effect of flicker on the live view image, and then captures the image for live view display. Specifically, the charge accumulation time is set to an integer multiple of the flicker period. The CPU 104 periodically performs photometry using the live view image even during the capture of the image for live view display, and performs exposure calculation (exposure control) based on the photometry results.

[0032] There are two factors that can cause the live view display to be interrupted: a power-off operation and an image capture operation. In step S106, CPU 104 determines whether or not a power-off operation has been performed by the user. If a power-off operation has been performed, in step S122 the live view display is interrupted and the power to camera body 100 is turned off. On the other hand, if a power-off operation has not been performed, the process proceeds to step S107.

[0033] In step S107, the CPU 104 determines whether or not an image capturing operation has been performed by the user (an image capturing instruction issued by a full press of the image capturing instruction unit 110). If an image capturing operation has been performed, the CPU 104 suspends image capturing for live view display and executes flicker detection and flickerless image capturing from step S118 onward. On the other hand, if an image capturing operation has not been performed, the CPU 104 returns to the processing of step S104.

[0034] In this step, instead of determining whether an image capture operation has been performed, it may be determined whether an image capture preparation instruction has been issued by the user half-pressing the image capture instruction unit 110. In this case as well, if an image capture preparation instruction has been issued, the processing from step S118 onwards is performed, and if an image capture preparation instruction has not been issued, the processing returns to step S104.

[0035] Here, the processing of steps S114 to S117 when no flicker is detected in step S102 will be described. The processing when no flicker is detected is basically the same as the processing when flicker is detected, as described above. However, when no flicker is detected, in step S114, CPU 104 does not need to control the charge accumulation time of image sensor 101 in accordance with the flicker cycle, and therefore performs exposure control to optimize the charge accumulation time based on the photometry results.

[0036] In this way, as exposure control for acquiring a live view image when flicker is detected, the charge accumulation time of the image sensor 101 is controlled to reduce the effects of flicker, thereby effectively reducing the effects of flicker on the live view image.

[0037] In step S118, immediately before continuous image capture, the CPU 104 detects flicker and calculates the peak timing of the change in light intensity of the flicker. The flicker period and the peak timing of the change in light intensity of the flicker are calculated, for example, based on the photometric value from the image data obtained by continuously storing and reading charge at 600 fps (approximately 1.667 ms cycle) of the image sensor 101 12 times. Explanation of the calculation method will be omitted.

[0038] If flicker is detected in step S118, CPU 104 performs continuous imaging using flickerless imaging synchronized with the peak timing of the flicker in step S119. Details of this process will be described later. On the other hand, if flicker is not detected in step S118, CPU 104 performs normal continuous imaging not dependent on the peak timing of the flicker in step S121.

[0039] As described above, in this embodiment, flicker detection is performed immediately before continuous image capture, and if flicker is detected, flicker-free image capture is performed with a charge accumulation time of the image sensor 101 that matches the characteristics of the change in light amount of the flicker. This makes it possible to reduce the effects of flicker in still images for recording acquired during continuous image capture, and also to reduce the effects of flicker in live view images acquired between image captures.

[0040] (Flicker-free imaging during live view display) Next, details of the process (control method) for continuous imaging using flickerless imaging synchronized with the peak timing of flicker, which is executed in step S119 of Fig. 3, will be described using the flowchart of Fig. 4 and the timing charts of Fig. 5 and Fig. 6. In this process, different processing is performed depending on whether the time interval between each still image capture in continuous imaging (hereinafter referred to as the imaging frame interval) is equal to or greater than a predetermined value. The predetermined value is set to a time longer than the "charge accumulation time for reducing the effects of flicker" described above in imaging for live view display.

[0041] (When the frame interval is less than the specified value) 5 is a timing chart showing the processing when the frame interval is less than a predetermined value (shorter than a predetermined time). In step S201 in FIG. 4 (time 501 in FIG. 5), the CPU 104 causes the LPU 203 to control the aperture drive unit 205 so that the aperture value of the aperture 202 becomes the aperture value for capturing a still image.

[0042] Next, in step S202 (time 502), the CPU 104 captures a still image (first image) in the continuous image capturing. At this time, the CPU 104 controls the exposure so that the center of the exposure time of the image sensor 101 coincides with the peak timing of the change in light amount of the flicker obtained in step S118 of Fig. 3, thereby suppressing the influence of the flicker on the still image obtained by the still image capturing.

[0043] Next, in step S203, CPU 104 calculates the imaging frame interval, which is the time interval until the next still image is captured (second imaging). In Fig. 5, the interval between T1 and T2 corresponds to the imaging frame interval. The imaging frame interval is calculated using the following formula, for example, if an imaging frame interval with an exposure time of up to 1 ms can be guaranteed. When the exposure time is 1 ms or less Interval between capture frames [ms] = 1000 / set continuous capture speed When the exposure time exceeds 1 ms Interval between capture frames [ms] = 1000 / set continuous capture speed + exposure time Next, in step S204, the CPU 104 determines whether the frame interval calculated in step S203 is equal to or greater than a predetermined value (e.g., 333 ms), and if it is less than the predetermined value, it performs processing in step S205, and if it is equal to or greater than the predetermined value, it performs processing in step S209.

[0044] In step S205 (time 505), the CPU 104 calculates an exposure control value (exposure calculation) for capturing the next still image based on the photometric value obtained as the photometric result from the still image acquired in step S202.

[0045] Next, in step S206 (time 506), CPU 104 performs image capture for live view display. Because image capture for live view display is not synchronized with the peak timing of flicker, stripes may appear in the live view image if the exposure time is short. However, because the exposure control value is not calculated from the live view image, the resulting stripes will not affect the exposure of the next image capture.

[0046] Next, in step S207, the CPU 104 checks whether the user has withdrawn the image capturing operation (whether the operation of the image capturing instruction unit 110 has been stopped). If the image capturing operation has been withdrawn, the CPU 104 ends the continuous image capturing in step S220. If the image capturing operation has not been withdrawn, the CPU 104 performs the process of step S208.

[0047] In step S208, CPU 104 checks whether the preparation start time for capturing the next still image has passed. If the preparation start time has not passed, the process returns to step S206 and continues capturing image data for live view display. If the preparation start time has passed, the process returns to step S201 and performs aperture driving for capturing the next still image according to the exposure calculation result in step S205. Thereafter, CPU 104 captures the next still image in step S202 (time T2).

[0048] As explained above, if the frame interval is less than a predetermined value, exposure calculation for capturing the next still image is performed from the still image obtained by capturing still images in continuous shooting. This makes it possible to perform appropriate exposure calculation (i.e., exposure control) for capturing the next still image, even if the exposure time for capturing live view display is short and stripes appear in the live view image.

[0049] (When the frame interval is greater than or equal to a specified value) 6 is a timing chart showing the processing when the image capture frame interval is equal to or greater than a predetermined value (longer than a predetermined time). If the image capture frame interval is equal to or greater than the predetermined value in step S201 of FIG. 4 (time 501 of FIG. 5), CPU 104 performs the processing of step S209.

[0050] In step S209 (time 609 in FIG. 6), the CPU 104 performs image capture for live view display with a charge accumulation time that reduces the effects of flicker. In FIG. 6, the charge accumulation time is set to twice the flicker cycle, for example.

[0051] Next, in step S210 (time 610), CPU 104 performs exposure calculation for capturing the next still image based on the photometric value obtained as the photometric result from the live view image acquired in step S209. If exposure calculation has been performed multiple times before capturing the next still image, the most recent calculation result is used as the exposure control value for capturing the next still image.

[0052] The processes in steps S211 and S212 are the same as those in steps S207 and S208, respectively.

[0053] As explained above, when the frame interval is equal to or greater than a predetermined value, live view display image capture is performed with a charge accumulation time that reduces the effects of flicker, and the live view image obtained is used to perform appropriate exposure calculations (i.e., exposure control) for capturing the next still image. This makes it possible to improve exposure tracking during continuous image capture with long frame intervals. [Example]

[0054] Next, a second embodiment of the present invention will be described. In the first embodiment, in step S209, imaging for live view display is performed using a charge accumulation time that reduces the effects of flicker, so there is a restriction on the lower limit of the charge accumulation time. If the restriction on the charge accumulation time results in overexposure, it is necessary to adjust the exposure for imaging for live view display by lowering the ISO sensitivity or narrowing the aperture 202 to achieve proper exposure. In this embodiment, control is performed to narrow the aperture 202 before starting imaging for live view display after capturing a still image, thereby adjusting the exposure for imaging for live view display.

[0055] The flowchart in Fig. 7 shows the process of continuous imaging by flickerless imaging synchronized with the peak timing of flicker, which is executed in this embodiment in step S119 in Fig. 3. In this process, different processing is performed depending on whether the interval between images captured in continuous imaging is equal to or greater than a predetermined value.

[0056] (When the frame interval is less than the specified value) In this case, CPU 104 performs the processes of steps S701 to S708, S720, and S731 in Fig. 7. The processes other than step S731 are the same as the processes of steps S201 to S208 and S220 in Fig. 4, and therefore their explanation will be omitted. The left side of Fig. 8 shows a timing chart of the processes when the image capture frame interval is less than a predetermined value.

[0057] In step S731, the CPU 104 drives the aperture 202 as necessary before starting imaging for live view display in step S706. At this time, a limit is set on the difference between the aperture value for imaging for live view display and the aperture value for imaging a still image.

[0058] 5 used in Example 1 shows a case where the difference between the aperture value in live view display imaging and the aperture value in still image imaging (first and second imaging) is smaller than a limit value (predetermined value). By controlling in this way, it is possible to prevent the imaging frame interval from becoming longer due to driving of the aperture 202 when the imaging frame interval is less than the predetermined value.

[0059] (When the frame interval is greater than or equal to a specified value) In this case, CPU 104 performs the processes of steps S701 to S704, S730, S709 to S712, and S720 in Fig. 7. The processes other than step S730 are the same as the processes of steps S201 to S204, S209 to S212, and S220 in Fig. 4, and therefore their explanation will be omitted. Fig. 8 shows a timing chart of the processes when the image capture frame interval is equal to or greater than a predetermined value.

[0060] In step S730 (time 830 in FIG. 8), CPU 104 drives aperture 202 to an aperture value that will make the live view image an image with proper exposure. At this time, no limit is placed on the difference between the aperture value used for capturing images for live view display and the aperture value used for capturing still images (first and second captures) in step S701. In other words, the difference is allowed to be greater than the above-mentioned limit value.

[0061] By such control, it is possible to widen the range of subject luminance (dynamic range of photometry) that allows obtaining appropriate photometric values ​​for capturing still images.

[0062] As described above, when the frame interval is equal to or greater than a predetermined value, no restrictions are imposed on the control of the aperture 202 before capturing images for live view display, as is the case when the frame interval is less than the predetermined value. This makes it possible to capture still images with appropriate exposure even when there is a large fluctuation in exposure. [Example]

[0063] Next, a third embodiment will be described. In the first embodiment, in step S204, whether to perform exposure calculation from a live view image or a still image was determined depending on whether the frame interval between images was equal to or greater than a predetermined value. However, if proper photometry is possible when capturing images for live view display using an aperture value for still image capture and a charge accumulation time that reduces the effects of flicker (i.e., the exposure time for display capture is longer than the predetermined exposure time), performing exposure calculation from a live view image is expected to improve exposure tracking. In this embodiment, processing is performed taking this into consideration.

[0064] The flowchart in Fig. 9 shows the process of continuous imaging by flickerless imaging synchronized with the peak timing of flicker, which is executed in this embodiment in step S119 in Fig. 3. The processes of steps S901 to S920 other than step S904 are the same as steps S201 to S203 and steps S205 to S220 in the first embodiment.

[0065] In step S904, the CPU 104 determines whether "the frame interval between images is equal to or greater than a predetermined value" or "proper metering is possible when capturing images for live view display with a charge accumulation time that reduces the effects of flicker." Whether proper metering is possible is determined from a) the most recent photometry result, b) aperture value, c) the control range of charge accumulation time that reduces the effects of flicker, and d) the control range of ISO sensitivity.

[0066] If "the frame interval is equal to or greater than a predetermined value" or "appropriate metering is possible when image capture for live view display is performed with a charge accumulation time that reduces the effects of flicker," the CPU 104 performs exposure calculations from the live view image in step S910 after passing through step S909. If "the frame interval is equal to or greater than a predetermined value" or "appropriate metering is possible when image capture for live view display is performed with a charge accumulation time that reduces the effects of flicker" is not true, the CPU 104 performs exposure calculations from a still image in step S905.

[0067] As described above, when proper photometry can be performed from a live view image under a flickering light source, exposure tracking can be improved by performing exposure calculations from the live view image regardless of the frame interval. [Example]

[0068] Next, a fourth embodiment will be described. In the second embodiment, in step S704, whether exposure calculation is performed from a live view image or a still image is determined based on whether the frame interval is equal to or greater than a predetermined value. However, when exposure calculation is performed from a live view image in step S730, there is a possibility that aperture drive noise will be generated when the aperture 202 is driven to an aperture value for capturing images for live view display. For this reason, in this embodiment, when a setting is made in the camera body 100 that prioritizes quietness as a setting related to its operation noise, the aperture 202 is driven at a slower speed than when this setting is not made, thereby reducing the aperture drive noise as an operation noise.

[0069] The flowchart in Fig. 10 shows the process of continuous imaging by flickerless imaging synchronized with the peak timing of flicker, which is executed in this embodiment in step S119 in Fig. 3. The processes of steps S1101 to S1131 other than step S1104 and step S1130 are the same as steps S701 to S703, steps S705 to S720, and step S731 in the second embodiment.

[0070] In step S1004, CPU 104 determines whether the conditions of "the image capture frame interval is equal to or greater than a predetermined value" and "a setting other than a setting that prioritizes quietness" are met. If these conditions are met, in step S1130, CPU 104 slowly drives aperture 202 to an aperture value that will make the live view image an image with proper exposure. At this time, no limit is placed on the difference between the aperture value for capturing images for live view display and the aperture value for capturing still images. Then, in step S1110, CPU 104 performs exposure calculations from the live view image.

[0071] On the other hand, if the above conditions are not satisfied, the CPU 104 performs exposure calculation from the still image in step S1105.

[0072] As described above, when a setting is made to prioritize quietness, quietness can be improved by driving the diaphragm 202 at a low speed.

[0073] In the above embodiments, the processing during continuous image capture in continuous shooting mode has been described, but the processing of each embodiment can also be performed when multiple individual images are captured by, for example, repeating full-press and half-press operations of the image capture instruction unit 110.

[0074] The above embodiment includes the following configurations.

[0075] (Configuration 1) An imaging device that performs image capture for display to obtain an image for display between a first image capture for obtaining an image for recording and a subsequent second image capture, photometry means for performing photometry using an image; a control means for controlling exposure in accordance with the result of the photometry; The control means controls exposure in the second image capture when flicker is included in the light incident on the image capture device, when the interval between the first image capture and the second image capture is shorter than a predetermined time, performing the photometry in accordance with a result of the photometry using the image for recording acquired in the first image capture; When the interval is longer than the predetermined time, the image pickup device performs the photometry in accordance with the result of the photometry using the display image. (Configuration 2) 2. The imaging device according to configuration 1, wherein the first imaging and the second imaging are each one imaging in a continuous imaging sequence. (Configuration 3) 3. The imaging device according to configuration 1 or 2, further comprising a detection means for detecting whether the light contains flicker. (Configuration 4) 4. The imaging device according to any one of configurations 1 to 3, wherein the predetermined time is longer than a time that is an integral multiple of the period of the flicker. (Configuration 5) The control means controlling the aperture value in accordance with the result of the photometry; When the light includes the flicker, When the interval is shorter than the predetermined time, the difference between the aperture value in the first and second imaging and the aperture value in the imaging for display is limited to be smaller than a predetermined value; 5. The imaging device according to any one of configurations 1 to 4, wherein when the interval is longer than the predetermined time, no limit is imposed on the difference. (Configuration 6) The control means When the light includes the flicker, The imaging device according to any one of configurations 1 to 5, characterized in that when the exposure time in the image for display is longer than a predetermined exposure time, even if the interval is shorter than the predetermined time, exposure control in the second image is performed according to the result of the photometry using the image for display. (Configuration 7) 7. The imaging device according to configuration 6, wherein the predetermined exposure time is an integral multiple of the period of the flicker. (Configuration 8) The control means Controlling the driving of the diaphragm in accordance with the result of the photometry; 8. The imaging device according to any one of configurations 1 to 7, wherein when a setting related to the operation sound of the imaging device is made, the aperture is driven at a slower speed than when the setting is not made.

[0076] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0077] The embodiments described above are merely representative examples, and various modifications and alterations are possible to each embodiment when implementing the present invention. [Explanation of symbols]

[0078] 100 camera body 101 Image sensor 104 System control unit (CPU)

Claims

1. An imaging device that performs a display image acquisition between a first image acquisition for recording and a second image acquisition, wherein the display image acquisition is performed between these two images. A photometric means that performs photometry using an image, A detection means for detecting flicker, It has a control means that performs exposure control according to the results of the photometric measurement, The control means controls the exposure in the second image when the detection means detects flicker. When the interval between the first imaging and the second imaging is shorter than the period of the flicker, the photometric measurement is performed according to the result of the recording image acquired in the first imaging. The imaging device is characterized in that if the interval is greater than or equal to the period of the flicker, the procedure is performed according to the results of the photometric measurement using the display image.

2. The imaging apparatus according to claim 1, characterized in that the first imaging and the second imaging are each one imaging in continuous imaging.

3. The control means is The aperture value is controlled according to the results of the photometering. When the light incident on the imaging device includes the flicker, When the interval is shorter than the flicker period, the difference between the aperture value in the first and second imaging and the aperture value in the display imaging is limited to be smaller than a predetermined value. The imaging apparatus according to claim 1, characterized in that the limit on the difference is not set when the interval is greater than or equal to the period of the flicker.

4. The control means is The aperture drive is controlled according to the results of the photometric measurement. The imaging device according to claim 1, characterized in that, when a setting for the operating noise of the imaging device is made, the aperture is driven at a lower speed than when no such setting is made.

5. A control method for an imaging device, comprising: performing a display image acquisition between a first image acquisition for recording and a second image acquisition; performing photometry using the image; and controlling the exposure according to the results of the photometry, A detection step for detecting flicker, A photometric step in which photometry is performed using the acquired image, The system includes an exposure control step that controls the exposure based on the results of the photometric step, If flicker is detected in the above detection step, In the exposure control step, the exposure control for the second imaging is performed as follows: When the interval between the first imaging and the second imaging is shorter than the period of the flicker, the photometric measurement is performed according to the result of the recording image acquired in the first imaging. A control method characterized in that when the interval is greater than or equal to the period of the flicker, the control is performed according to the results of photometric measurement using the display image.

6. A program characterized by causing a computer to execute each of the means of the imaging apparatus described in any one of claims 1 to 4.

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