JP2018207455A - Imaging apparatus, method for controlling the same, program, and storage medium - Google Patents

Abstract

To provide an imaging apparatus capable of performing photographing for highly accurately reducing the influence of a flicker, even during the enlargement of the image of a specific area by a live view.SOLUTION: The imaging apparatus includes a switching part which switches a first display mode in which the image signal of a predetermined screen is displayed on a display part and a second display mode in which the image signal of a part of the predetermined screen is displayed on the display part, a flicker detection part which detects the flicker, a setting part which sets a flicker reduction photography mode for acquiring an image in which the influence of the flicker is reduced, and an exposure control part which controls at least an exposure time, to acquire the image in which the flicker is reduced in the flicker reduction photography mode. In such a state that the flicker reduction photography mode is set by the setting mode and the second display mode is set by the switching part, the exposure control part controls the exposure time of an imaging part to the exposure time for reducing the influence of the flicker, without depending on the result of the detection of the flicker by the flicker detection part.SELECTED DRAWING: None

Description

  The present invention relates to an imaging apparatus capable of imaging with reduced influence of exposure unevenness caused by flicker.

  In general, in an imaging apparatus such as a digital camera, when a subject is imaged in a state where a periodic light amount change (so-called flicker) of an artificial light source occurs, exposure and color unevenness due to the effect of flicker are added to the captured image. May occur.

  To deal with this problem, for example, Patent Document 1 acquires an image that is not affected by flicker and an image that is affected by flicker, and detects a flicker light amount change period, a peak position, and the like based on a comparison result of the two images. Techniques to do this have been proposed. Patent Document 1 discloses that an image that is not affected by flicker is used for live view (hereinafter simply referred to as LV) display on a monitor.

  On the other hand, in an image sensor capable of reading a specific area, an enlarged image (so-called digital zoomed image) can be acquired by setting the read area to be smaller than the entire area constituting the image sensor. (Image enlarged display). For example, Patent Document 2 proposes a method for performing high-resolution zoom by changing the readout range of the image sensor and the driving method.

Japanese Patent Laying-Open No. 2015-88917 JP 2002-314868 A

  However, in the prior art disclosed in the above-mentioned patent document, the following problems occur when detecting the flicker light amount change period and the peak position while reading out a specific area.

  For example, if the image enlargement display as described above is performed in order to confirm the focus state on the subject during LV display, the flicker is correctly detected when the flicker light source exists outside the area where the image signal is read out. There are cases where it is not possible. In this case, it is difficult to correctly reduce the effect of flicker.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an imaging apparatus capable of accurately performing shooting with reduced influence of flicker while enlarging an image of a specific area by live view. That is.

  An imaging apparatus according to the present invention includes an imaging unit that images a subject, a first display mode that displays an image signal of a predetermined screen corresponding to the imaging unit on a display unit, and the predetermined unit that corresponds to the imaging unit. Flicker detection for detecting flicker of illumination light of the subject using switching means for switching between a second display mode for displaying a part of the image signal of the screen on the display means and an image signal output from the imaging means Means for setting a flicker reduction shooting mode for capturing an image of a subject and acquiring an image with reduced influence of the flicker; and for acquiring an image with reduced flicker in the flicker reduction shooting mode. Exposure control means for controlling at least the exposure time of the image pickup means, and the setting means for the flicker reduction shooting mode. Is set and the second display mode is set by the switching means, the exposure control means sets the exposure time of the imaging means to the exposure time regardless of the result of flicker detection by the flicker detection means. The exposure time is controlled to reduce the influence of flicker.

  According to the present invention, even when an image of a specific area is enlarged by live view, it is possible to perform shooting with reduced influence of flicker with high accuracy.

1 is a diagram illustrating a configuration of a digital single-lens reflex camera system that is a first embodiment of an imaging apparatus of the present invention. FIG. The figure which shows the read-out area | region in LV, and its display state. The figure which shows the process example of the flicker detection of a 1st system. The flowchart which shows the operation | movement of the flicker detection of a 1st system. The figure which shows the process example of the flicker detection of a 2nd system. Flowchart showing operation of flicker detection of the second method The figure which shows the shutter control for flickerless imaging | photography. 6 is a flowchart showing an operation of flickerless shooting. 6 is a flowchart of a flickerless shooting operation during LV enlargement in the first embodiment. 10 is a flowchart of a flickerless shooting operation during LV enlargement in the second embodiment. 10 is a flowchart of a flickerless shooting operation during LV enlargement in the third embodiment. 10 is a flowchart of a flickerless shooting operation during LV enlargement in the fourth embodiment. 10 is a flowchart of a flickerless shooting operation during LV enlargement in the fifth embodiment.

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

(First embodiment)
FIG. 1 is a diagram showing a configuration of a digital single-lens reflex camera system which is a first embodiment of an imaging apparatus of the present invention.

  In FIG. 1, the digital single-lens reflex camera system includes a camera body 101 and a photographing lens 102 that is attached to the camera body 101 in a replaceable manner. The camera body 101 and the taking lens 102 are mechanically and electrically connected to each other. The taking lens 102 includes a focusing lens 103 and a diaphragm 104, and is controlled from the camera body 101 via a lens mount contact group 105.

  The main mirror 106 is a half mirror, and a sub mirror 107 is disposed on the back surface. In the state shown in FIG. 1 where the mirror is not raised, a part of the light beam from the photographing lens 102 is reflected by the main mirror 106 and is incident on the upper finder screen 109. A part of the light beam transmitted without being reflected by the main mirror 106 is reflected by the sub mirror 107 and is incident on the AF device (autofocus device) 108 below. The AF device 108 includes a phase difference detection type focus detection sensor. The focus detection sensor converts the light collected by the photographing lens 102 and incident through the sub mirror 107 into an electrical signal, and outputs an image signal in each focus detection region.

  The light beam reflected by the main mirror 106 is imaged on the finder screen 109 to form a subject image. The subject image formed on the finder screen 109 is guided to the photographer's eyes through the pentaprism 111 and the eyepiece 110, and is visually recognized by the photographer. The subject image formed on the finder screen 109 is guided to the AE device (automatic exposure device) 112 via the pentaprism 111.

  The AE device 112 includes a photometric sensor, and converts the optical viewfinder image into a photometric image. Further, the AE device performs automatic exposure calculation based on the photometric image continuously read from the photometric sensor, and outputs it to the CPU 116. The CPU 116 controls the opening amount of the diaphragm 104 of the photographing lens 102 based on the output result of the automatic exposure calculation, and adjusts the amount of light incident through the photographing lens 102. Further, the CPU 116 performs photometric calculation, subject tracking, flicker detection calculation, and the like using the photometric image generated by the photometric sensor. The camera body 101 includes a nonvolatile memory 117 such as a ROM and a system memory 118 such as a RAM. Then, a program or the like stored in the nonvolatile memory 117 is expanded in the system memory 118, and the CPU 116 controls the entire camera system by executing the expanded program. The system memory 118 is also used as a work area for the CPU 116. In addition, a recording medium 119 such as a memory card is detachably disposed on the camera body 101, and captured image data is recorded.

  The image sensor 113 is composed of a CMOS image sensor, a CCD image sensor, or the like in which a plurality of pixels having photoelectric conversion elements are arranged. When photographing, the main mirror 106 and the sub mirror 107 are moved from the photographing optical path, and the imaging element 113 is exposed by opening the focal plane shutter 114, and a subject image is captured. The image sensor 113 converts light incident through the photographing lens 102 during exposure into an electrical signal at each pixel, further A / D converts it to form image data, and outputs it to the CPU 116. The CPU 116 performs predetermined image processing and the like on the image data output from the image sensor 113 and displays the data on the monitor 115. In addition, photometric calculation, subject tracking, and flicker detection calculation, which are characteristic operations of the present embodiment, are performed using image data.

  In addition, when performing normal LV display (live view display), image processing is not performed on signals from all pixels arranged on the imaging surface of the image sensor 113 and is not displayed on the monitor 115. Since full-screen display is performed at a fixed frame rate, pixel signals are added or thinned out based on the readout speed of signals from each pixel of the image sensor 113, the processing speed of the CPU 116, the display rate of the monitor 115, etc. Display images with low resolution.

  The monitor 115 displays not only the captured image but also a GUI for performing various settings and control of the camera system. In this embodiment, an enlargement setting / enlargement release button for confirming the focus is displayed, and enlargement display and enlargement display cancellation are performed by an operation from the user. When performing enlarged LV display (enlarged live view display), a specific area to be enlarged is determined based on the readout speed of a signal corresponding to each pixel of the image sensor 113, the processing speed of the CPU 116, the display rate of the monitor 115, and the like. Only the signals of some of the pixels arranged in are read out. Then, image processing is performed on the read pixel data, and a partial but high resolution image is displayed. The GUI of the monitor 115 also displays a button for the user to select and switch between a normal shooting mode and a flicker reduction mode for shooting that reduces flicker of the light source.

  Here, the influence of flicker of the light source (illumination light) in the camera system of the present embodiment will be described.

  As described above, in general, in an imaging device such as a digital camera, if a subject is imaged in a state where a periodic light amount change (so-called flicker) of an artificial light source occurs, the effect of flicker is exerted on the captured image. May cause exposure and color unevenness. In such a case, an imaging apparatus that detects an flicker and adjusts an imaging timing or a shutter speed so as not to be affected by the detection has been proposed.

  However, as in this embodiment, in a camera system capable of magnifying and displaying an image in order to confirm the focus state on the subject during LV (live view) display, flicker is correctly performed during magnifying display. It may not be detected. That is, if the flicker light source exists outside the specific area from which the image signal is read, there is a case where the influence of the flicker does not appear in the specific area, and the flicker cannot be detected correctly. If flicker cannot be correctly detected during enlarged display in the LV operation, exposure unevenness due to the effect of flicker occurs in the still image shooting that involves subsequent full reading.

  This problem will be described in more detail. FIG. 2 is a diagram showing a read area in the LV and a display image thereof. In the entire area A, it is assumed that there are an area A-1 that is affected by the flicker light source and an area A-2 that is not affected by the flicker light source. Region B represents a readout region and its display image when an area A-1 is enlarged. A region C represents a readout region and its display image when an area of the region A-2 is enlarged and displayed. During the enlarged display of the area B, flicker detection is possible because the read area has light and dark due to the influence of the flicker light source. However, during the enlarged display of the area C, since the read area does not have light and darkness due to the flicker light source, the flicker light source existing in the area B cannot be detected. That is, when the entire area A is shot by the release operation during the enlarged display of the area C, the camera determines that there is no flicker effect, and therefore flickerless shooting that reduces the influence of the flicker light source is not performed.

  In the camera system of the present embodiment, the user can switch between a normal shooting mode and a flicker reduction shooting mode in which shooting is performed to reduce flicker of a light source. When the user selects the flicker reduction shooting mode, the camera body 101 performs an operation specific to the present embodiment as described in detail later.

  Next, the first and second types of flicker detection are performed in the present embodiment. The first method of flicker detection in the present embodiment will be described with reference to FIGS. FIG. 3 is a diagram showing an example of shutter drive and flicker detection processing in the first method of flicker detection in the present embodiment. FIG. 4 is a flowchart showing the flicker detection operation of the first method during LV display (including normal display (first display mode) and enlarged display (second display mode)) in the present embodiment. It is. Here, a case where 100 Hz flicker is generated will be described as an example. Note that the operation shown in the flowchart of FIG. 4 is performed by the CPU 116 executing a program stored in the nonvolatile memory 117.

  First, in step S401, the CPU 116 controls the image sensor 113 to perform first accumulation and acquires an image (FIG. 3: image A). At this time, by controlling the accumulation time to be 10 ms, which is the same as the flicker cycle, an image not affected by flicker is acquired. The acquired image is used for display on the monitor 115 in the next step S402.

  Subsequently, in step S403, the CPU 116 controls the image sensor 113 to perform second accumulation, and acquires an image (FIG. 3: image B). At this time, by controlling the accumulation time to be sufficiently shorter than the flicker cycle, for example, 1 ms, an image affected by the flicker is acquired.

  In step S404, the CPU 116 calculates the ratio of the image A and the image B as shown in the lower part of FIG. 3, thereby generating an image B ′ in which the flicker component is extracted from the image B. A flicker waveform is obtained from the generated image B ', and the peak timing of the intensity of the light source is calculated in step S405. At this time, when the peak timing is calculated for the first time, the determination in step S406 is NO, and the process returns to step S401. Steps S401 to S405 are executed again to obtain the images C and D in FIG. 3, and an image D ′ is generated from the ratio of the two images. Then, the flicker waveform is obtained from the generated image D ′, and the peak timing of the light source intensity is calculated. When the second peak timing calculation is completed, the determination in step S406 becomes YES, and the process proceeds to step S407.

  In step S407, the CPU 116 determines the flicker cycle from the calculated time difference between the two peak timings, and the process ends. The detailed algorithm / calculation method for flicker detection of the first method is disclosed in Patent Document 1 and the like and is a known technique, and thus detailed description thereof is omitted here. In the first method of flicker detection according to the present embodiment, the obtained image is divided into a plurality of areas, and flicker detection is performed based on the ratio of each area. Thus, even when flicker is generated only in a part of the screen (left part in FIG. 3) like images E, F and E ′ shown in the lower part of FIG. 3, flicker is detected. Is possible.

  Next, the second type of flicker detection in this embodiment will be described with reference to FIGS. FIG. 5 is a diagram illustrating an example of shutter driving and flicker detection processing in flicker detection of the second method in the present embodiment. FIG. 6 is a flowchart showing the flicker detection operation of the second method in the present embodiment. The operation shown in the flowchart of FIG. 6 is performed by the CPU 116 executing a program stored in the nonvolatile memory 117.

  First, in step S601, the CPU 116 controls the image sensor 113 to acquire images continuously 12 times at a predetermined frame rate. Here, the predetermined frame rate is about 600 Hz. That is, 6 images are acquired during 10 ms of flicker, and 12 images are acquired during 2 cycles. Subsequently, an integral value of the luminance of the entire screen is obtained for each image acquired in step S602. In step S603, the flicker cycle is determined from the transition of the integral value obtained for each image. In step S604, the flicker peak timing is calculated from the integral value, and the process ends.

  The detailed algorithm / calculation method for flicker detection of the second method is disclosed in Patent Document 1 and the like and is a known technique, and thus detailed description thereof is omitted here. In the second flicker detection in Patent Document 1, a plurality of images are acquired at a predetermined frame rate, and the flicker waveform is calculated from the luminance change of the entire screen. However, in the present embodiment, the obtained image is divided into a plurality of areas, and flicker detection is performed based on the luminance change for each area. Accordingly, as shown in the lower part of FIG. 5, it is possible to detect the flicker even when the flicker is generated only in the lower part of the surface.

  Next, flickerless shooting exposure control in the camera system of this embodiment will be described with reference to FIG. FIG. 7 is a diagram illustrating shutter control for capturing an image that is not affected by flicker according to the flicker waveform. Here, a case will be described in which flicker detection is completed before a shooting instruction is issued by pressing a release switch (not shown). When flicker is detected by the flicker detection processing, the flicker peak timing is detected, and accordingly, a flicker tuning signal for synchronizing the flicker peak and the photographing timing is continuously output. If a shooting instruction is issued by pressing the release switch in the meantime, exposure is not performed as indicated by the broken line S1 at the timing immediately after the shooting instruction indicated by R in FIG. 7, but flicker indicated by the solid line S2 in FIG. Exposure is performed by driving the shutter at a timing in accordance with the output of the tuning signal F. As a result, exposure timing is controlled in accordance with the flicker peak timing every time shooting is performed, and variations in exposure can be suppressed. In other words, shooting that is not affected by flicker can be realized.

  Here, the case where flicker is detected before the release switch is pressed has been described. However, even when flicker detection processing is performed after the release switch is pressed, a tuning signal is output after flicker is detected, and shutter and exposure control are performed in accordance with the signal.

  Next, flickerless shooting in the present embodiment will be described using the flowchart of FIG. Note that the operation shown in the flowchart of FIG. 8 is performed by the CPU 116 executing a program stored in the nonvolatile memory 117.

  First, in step S801, the CPU 116 performs the first type of flicker detection. This first type of flicker detection is as already described with reference to FIGS. In step S <b> 802, the CPU 116 determines whether or not the LV enlarged display for confirming the focus is set using the GUI of the monitor 115. If it is determined that the LV enlarged display is not set, the process proceeds to step S809.

  In step S809, the CPU 116 determines whether a release switch (not shown) has been pressed. If it is determined that the release switch has not been pressed, the CPU 116 returns to step S801 and repeats the processing from step S801. If it is determined that the button has been pressed, the process proceeds to step S810. In step S810, the CPU 116 determines whether or not the flicker detection result of the first method is under a flicker light source. If it is determined that the light source is under a flicker light source, the process proceeds to step S811. In step S811, flickerless shooting processing is performed based on the result of flicker detection of the first method, and the process ends. This flickerless photographing process is as already described with reference to FIG.

  If it is determined in step S810 that the flicker light source is not under the flicker detection of the first method, the process proceeds to step S812. In step S812, since there is no flicker effect, normal shadow processing is performed and the process ends.

  On the other hand, if it is determined in step S802 that LV enlarged display is set, the process proceeds to step S803. In step S803, the CPU 116 performs processing for storing flicker information before LV expansion. In the flicker information storage process before LV enlargement, information of the result of the first method flicker detection performed in step S801 is stored in a storage area in the CPU 116.

  In step S804, the CPU 116 performs the first method of flicker detection in the LV expansion state. In the flicker detection of the first method during LV enlargement, a read image of a specific area when performing the enlarged display described with reference to FIG. 2 is used, and the first method described with reference to FIGS. 3 and 4 is used. Perform flicker detection. As described above, in the first method of flicker detection during LV enlargement, even if there is actually flicker, there is a case where there is no contrast due to the flicker light source in the read specific area, and the flicker light source is correctly detected as the entire screen. May not be possible.

  In step S805, the CPU 116 determines whether a release switch (not shown) has been pressed. If it is determined that the release switch has not been pressed, the process proceeds to step S808. In step S <b> 808, the CPU 116 determines whether cancellation of LV enlargement display for confirming the focus is set using the GUI of the monitor 115. When it is determined that the cancellation of the LV enlarged display is set, the processes after step S801 are repeated, and when it is determined that the cancellation of the LV enlarged display is not set, the processes after step S804 are repeated.

  On the other hand, if it is determined in step S805 that the release switch has been pressed, the process proceeds to step S806. In step S806, the CPU 116 performs processing for storing flicker information during LV expansion. In the flicker information storing process during LV expansion, the result information of the flicker detection of the first method during LV expansion performed in step S804 is stored in the storage area in the CPU 116.

  In step S807, the CPU 116 performs flickerless shooting during LV enlargement and ends. The above is the procedure of the flickerless shooting operation in the present embodiment.

  FIG. 9 is a flowchart showing the flickerless shooting operation during LV enlargement in step S807 of FIG.

  First, in step S901, the CPU 116 sets the shutter speed to a time that is necessarily longer than the flicker cycle. Specifically, by setting the exposure time longer than 1/50 (second), the shutter speed is not affected by either the 60 Hz flicker light source or the 50 Hz flicker light source. In this way, even if the flicker peak timing cannot be detected, an image that is not affected by the flicker can be taken.

  Next, in step S902, the CPU 116 opens the focal plane shutter 114, executes a shooting process for exposing the image sensor 113 at the shutter speed set in step S901, and ends.

  As described above, according to the first embodiment, it is possible to accurately perform shooting with reduced influence of flicker even when an image of a specific region is enlarged by live view. In addition, since flicker detection processing is not performed again during LV enlargement, the time lag until actual shooting when the release switch is pressed can be reduced.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described. In the second embodiment, the configuration and operation of the digital single-lens reflex camera system are substantially the same as those of the first embodiment, and only the operation of flickerless shooting during LV enlargement in step S807 in FIG. 8 is different. Therefore, the description of the common parts with the first embodiment is omitted, and only the different parts are described.

  FIG. 10 is a flowchart showing the operation of flickerless shooting during LV enlargement in the second embodiment.

  First, in step S1001, the CPU 116 acquires the flicker information during LV expansion stored in step S806 of the flowchart of FIG. 8 from the storage area. In step S1002, it is determined from the acquired flicker light source information during LV expansion whether or not there is a flicker light source during LV expansion. If it is determined that there is a flicker light source, the process proceeds to step S1003. In step S1003, based on the flicker light source information during LV enlargement, the flickerless shooting process is completed according to the flickerless shooting operation already described with reference to FIG.

  On the other hand, if it is determined in step S1002 that there is no flicker light source during LV enlargement, the process proceeds to step S1004. In this case, as already described with reference to FIG. 2, even if flicker is not detected in the enlarged area, it is not determined that there is no flicker light source. In addition, since flicker is not detected in step S1001, even if there is actually flicker, the peak timing is not known. In other words, the flickerless shooting described with reference to FIG. 7 cannot be performed here. Therefore, in step S1004, the CPU 116 sets the shutter speed to a time that is necessarily longer than the flicker cycle. Specifically, by setting the exposure time longer than 1/50 (second), the shutter speed is not affected by either the 60 Hz flicker light source or the 50 Hz flicker light source.

  Next, in step S1005, the CPU 116 opens a focal plane shutter 114, executes an imaging process for exposing the image sensor 113 with the exposure time set in step S1004, and ends.

  As described above, also in the second embodiment, it is possible to accurately perform shooting with reduced influence of flicker even when an image of a specific area is enlarged by live view. In addition, the flicker detection process is not performed again during LV enlargement, and the information about the flicker detection process during LV enlargement in step S804 is used to reduce the time lag until actual shooting when the release switch is pressed. can do.

(Third embodiment)
Also in the third embodiment, the configuration and operation of the digital single-lens reflex camera system are almost the same as those of the first embodiment, and only the operation of flickerless shooting during LV enlargement in step S807 of FIG. 8 is different. Therefore, description of the parts common to the first and second embodiments is omitted, and only different parts are described.

  FIG. 11 is a flowchart showing the flickerless shooting operation during LV enlargement in the third embodiment.

  First, in step S1101, the CPU 116 acquires the flicker information during LV expansion stored in step S806 of the flowchart of FIG. 8 from the storage area. In step S1102, whether or not there is a flicker light source during LV expansion is determined based on the acquired flicker light source information during LV expansion. If it is determined that there is a flicker light source, the process proceeds to step S1103. In step S1103, based on the flicker light source information during LV enlargement, the flickerless photographing process is performed according to the flickerless photographing operation already described with reference to FIG.

  On the other hand, if it is determined in step S1102 that there is no flicker light source during LV enlargement, the process proceeds to step S1104. In this case, as already described with reference to FIG. 2, even if flicker is not detected in the enlarged area, it is not determined that there is no flicker light source. Therefore, in step S1104, the CPU 116 ends the LV enlarged display, switches to full screen display, and performs the second type of flicker detection described with reference to FIGS. Even if it is determined that there is no flicker during LV expansion, this is a process for reconfirming the presence or absence of flicker using the entire area. Here, the second type of flicker detection does not involve a display operation like the first type of flicker detection. Also, instead of determining the flicker waveform, the flicker is determined based on the luminance transition. Therefore, it is possible to shorten the number of processing times and time until flicker determination, make accurate determination, and reduce flicker detection time.

  In step S1105, the CPU 116 determines whether there is a flicker light source from the result of the flicker detection of the second method in step S1104. If it is determined that there is a flicker light source, the process proceeds to step S1106. In step S1106, based on the flicker light source information obtained by the flicker detection of the second method, the flickerless shooting process is completed according to the flickerless shooting operation already described with reference to FIG.

  On the other hand, if it is determined in step S1105 that there is no flicker light source, the process proceeds to step S1107. In step S1107, since flicker is not detected by flicker detection for all the screens in step S1104, it is determined that there is no influence of flicker, and normal photographing processing is performed and the process ends.

  As described above, also in the third embodiment, even when an image of a specific area is enlarged by live view, it is possible to accurately perform shooting with reduced influence of flicker. In addition, by using the information of the flicker detection process during LV expansion in step S804 or performing the flicker detection of the second method, an image that is not affected by the flicker is taken without slowing the shutter speed. Is possible.

(Fourth embodiment)
Also in the fourth embodiment, the configuration and operation of the digital single-lens reflex camera system are almost the same as those of the first embodiment, and only the operation of flickerless shooting during LV enlargement in step S807 of FIG. 8 is different. For this reason, description of parts common to the first to third embodiments is omitted, and only different parts are described.

  FIG. 12 is a flowchart showing the flickerless shooting operation during LV enlargement in the fourth embodiment.

  First, in step S1201, the CPU 116 acquires the flicker information during LV expansion stored in step S806 of the flowchart of FIG. 8 from the storage area. In step S1202, it is determined from the acquired flicker light source information during LV expansion whether or not there is a flicker light source during LV expansion. If it is determined that there is a flicker light source, the process advances to step S1203. In step S1203, based on the flicker light source information during LV enlargement, the flickerless shooting process is completed according to the flickerless shooting operation already described with reference to FIG.

  On the other hand, if it is determined in step S1202 that there is no flicker light source during LV enlargement, the process proceeds to step S1204. In step S1204, the flicker information before LV expansion stored in step S803 of the flowchart of FIG. 8 is acquired from the storage area. In step S1205, it is determined from the acquired flicker light source information before LV enlargement whether there is a flicker light source before LV enlargement. If it is determined that there is a flicker light source, the process advances to step S1203, and the flickerless shooting process is completed according to the flickerless shooting operation already described with reference to FIG. 7 based on the flicker light source information before LV enlargement. .

  On the other hand, if it is determined in step S1205 that there is no flicker light source before LV expansion, the process advances to step S1206. In step S1206, the CPU 116 sets the shutter speed to a time that is necessarily longer than the flicker cycle. Specifically, by setting the exposure time longer than 1/50 (second), the shutter speed is not affected by either the 60 Hz flicker light source or the 50 Hz flicker light source.

  In step S <b> 1207, the CPU 116 opens a focal plane shutter 114 to execute a shooting process for exposing the image sensor 113 with the exposure time set in step S <b> 901 and ends the process.

  In the flickerless shooting during LV enlargement in the fourth embodiment, it is possible to take an image that is not affected by flicker even for a subject that is partially affected by the flicker light source.

  As described above, also in the fourth embodiment, even when an image of a specific area is enlarged by live view, it is possible to accurately perform shooting with reduced influence of flicker. Also, the flicker detection process is not performed again during LV expansion, and the information of the flicker detection process during LV expansion in step S804 or the information of the flicker detection process before LV expansion in step S801 is used. The time lag until actual shooting when the switch is pressed can be reduced.

(Fifth embodiment)
Also in the fifth embodiment, the configuration and operation of the digital single-lens reflex camera system are almost the same as those of the first embodiment, and only the operation of flickerless shooting during LV enlargement in step S807 of FIG. 8 is different. For this reason, description of parts common to the first to fourth embodiments is omitted, and only different parts are described.

  FIG. 13 is a flowchart showing the flickerless shooting operation during LV enlargement in the fifth embodiment.

  First, in step S1301, the CPU 116 acquires the flicker information during LV expansion stored in step S806 of the flowchart of FIG. 8 from the storage area. In step S1302, it is determined from the acquired flicker light source information during LV expansion whether or not there is a flicker light source during LV expansion. If it is determined that there is a flicker light source, the process advances to step S1303. In step S1303, based on the flicker light source information during LV enlargement, the flickerless shooting process is performed according to the flickerless shooting operation already described with reference to FIG.

  On the other hand, if it is determined in step S1302 that there is no flicker light source during LV enlargement, the process proceeds to step S1304. In step S1304, the flicker information before LV expansion stored in step S803 of the flowchart of FIG. 8 is acquired from the storage area. In step S1305, it is determined from the acquired flicker light source information before LV enlargement whether there is a flicker light source before LV enlargement. If it is determined that there is a flicker light source, the process advances to step S1303, and the flickerless shooting process is completed according to the flickerless shooting operation already described with reference to FIG. 7 based on the flicker light source information before LV enlargement.

  On the other hand, if it is determined in step S1305 that there is no flicker light source before LV expansion, the process proceeds to step S1306. In this case, as already described with reference to FIG. 2, even if flicker is not detected in the enlarged area, it is not determined that there is no flicker light source. Therefore, in step S1306, the CPU 116 ends the LV enlarged display, switches to full screen display, and performs the flicker detection of the second method described with reference to FIGS. Even if it is determined that there is no flicker during LV expansion, this is a process for reconfirming the presence or absence of flicker using the entire area. Here, the second type of flicker detection does not involve a display operation like the first type of flicker detection. Also, instead of determining the flicker waveform, the flicker is determined based on the luminance transition. Therefore, it is possible to shorten the number of processing times and time until flicker determination, make accurate determination, and reduce flicker detection time.

  In step S1307, the CPU 116 determines whether there is a flicker light source from the result of the flicker detection of the second method in step S1306. If it is determined that there is a flicker light source, the process proceeds to step S1308. In step S1308, based on the flicker light source information obtained by the flicker detection of the second method, the flickerless shooting process is completed according to the flickerless shooting operation already described with reference to FIG.

  On the other hand, if it is determined in step S1307 that there is no flicker light source, the process advances to step S1309. In step S1309, since flicker is not detected in flicker detection for all the screens in step S1306, it is determined that there is no influence of flicker, and normal photographing processing is performed and the process ends.

  As described above, also in the fifth embodiment, it is possible to accurately perform shooting with reduced influence of flicker even when an image of a specific area is enlarged by live view. Further, by using the information of the flicker detection process during LV enlargement in step S804, the information of the flicker detection process before LV enlargement in step S801, or by performing the flicker detection of the second method, the shutter speed is reduced. An image that is not affected by flicker can be taken without delay.

  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)
In addition, the present invention supplies a program that realizes one or more functions of the above-described embodiment 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 the program. It can also be realized by executing processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

101: Camera body, 102: Shooting lens, 103: Focusing lens, 104: Aperture, 105: Lens mount contact group, 106: Main mirror, 107: Sub mirror, 108: AF device, 112: AE device, 113: Image sensor 114: Focal plane shutter, 115: Monitor

Claims (16)

Imaging means for imaging a subject;
A first display mode in which an image signal of a predetermined screen corresponding to the imaging unit is displayed on a display unit; and a second display mode in which a part of the image signal of the predetermined screen corresponding to the imaging unit is displayed on the display unit. Switching means for switching between display modes;
Flicker detection means for detecting flicker of illumination light of the subject using an image signal output from the imaging means;
Setting means for setting a flicker reduction shooting mode for capturing an image of a subject and acquiring an image with reduced influence of the flicker;
Exposure control means for controlling at least the exposure time of the imaging means in order to obtain an image with reduced flicker in the flicker reduction shooting mode,
In the state where the flicker reduction photographing mode is set by the setting means and the second display mode is set by the switching means, the exposure control means does not depend on the result of flicker detection by the flicker detection means. An image pickup apparatus that controls the exposure time of the image pickup means to an exposure time that reduces the influence of the flicker.   2. The imaging apparatus according to claim 1, wherein in the first display mode, the imaging unit thins out and outputs a predetermined pixel from a pixel of the predetermined screen corresponding to the imaging unit.   3. The imaging apparatus according to claim 1, wherein in the second display mode, the imaging unit outputs the partial image signal without being thinned. 4.   4. The imaging apparatus according to claim 1, wherein, in the second display mode, the partial image signal is enlarged and displayed on the display unit. 5.   The exposure control means acquires an image with reduced influence of the flicker by controlling only the exposure time of the imaging means when no flicker is detected by the flicker detection means. The imaging device according to any one of claims 1 to 4.   The imaging apparatus according to claim 5, wherein the exposure control unit acquires an image in which the influence of the flicker is reduced by making an exposure time of the imaging unit longer than a cycle of the flicker.   The said exposure control means acquires the image which reduced the influence of the said flicker by controlling the exposure time and exposure timing of the said imaging means, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. The imaging device described.   The exposure control means acquires an image with reduced influence of the flicker by controlling an exposure time and an exposure timing of the imaging means when flicker is detected by the flicker detection means. The imaging apparatus according to claim 7.   The flicker detection unit detects the flicker using the partial image signal when the flicker reduction photographing mode is set and the second display mode is set. The imaging device according to any one of claims 1 to 8.   The imaging apparatus according to claim 1, wherein the flicker detection unit detects the flicker by two kinds of methods.   The flicker detection means detects the flicker by dividing an image shot with an exposure time shorter than the flicker cycle by an image shot with the same exposure time as the flicker cycle; and The imaging according to claim 10, wherein the flicker is detected by a second method of detecting the flicker from a change in an integrated value of each of a plurality of images photographed with an exposure time shorter than a flicker cycle. apparatus.   12. The flicker detection unit according to claim 11, wherein the flicker detection unit detects the flicker by the second method when the flicker is not detected by the first method in the second display mode. Imaging device.   13. The imaging apparatus according to claim 12, wherein the flicker detection unit detects the flicker by the second method after switching from the second display mode to the first display mode. A method for controlling an imaging apparatus including an imaging means for imaging a subject,
A first display mode in which an image signal of a predetermined screen corresponding to the imaging unit is displayed on a display unit; and a second display mode in which a part of the image signal of the predetermined screen corresponding to the imaging unit is displayed on the display unit. A switching process for switching between display modes;
A flicker detection step of detecting flicker of illumination light of the subject using an image signal output from the imaging means;
A setting step for setting a flicker reduction shooting mode for capturing an image of a subject and acquiring an image with reduced influence of the flicker;
An exposure control step of controlling at least an exposure time of the imaging means in order to obtain an image with reduced flicker in the flicker reduction photographing mode;
In the state where the flicker reduction photographing mode is set in the setting step and the second display mode is set in the switching step, the exposure control step does not depend on the result of flicker detection in the flicker detection step. A method for controlling an imaging apparatus, wherein the exposure time of the imaging means is controlled to an exposure time that reduces the influence of the flicker.   The program for making a computer perform each process of the control method of Claim 14.   The computer-readable storage medium which memorize | stored the program for making a computer perform each process of the control method of Claim 14.