JP6742733B2 - Imaging device, control method thereof, and control program - Google Patents

Description

The present invention relates to an image pickup apparatus, a control method therefor, and a control program, and more particularly to control when a light-emitting device such as a strobe is caused to emit light to perform shooting.

In general, when a light emitting device such as a strobe is used to shoot an image, it is emphasized whether or not a subject illuminated by the strobe light can be shot with appropriate brightness. On the other hand, with the increase in sensitivity of the image sensor, when shooting against a dark background such as a night view, it is possible to shoot with a well-balanced brightness between the background that the strobe light does not reach and the subject illuminated by the strobe light. It has been demanded.

For example, if the shooting sensitivity is set to high sensitivity and shooting is performed, it is possible to shoot brightly even on a dark background such as a night view. However, if the strobe is used with the photographing sensitivity set to high sensitivity, the subject illuminated by the strobe light is likely to be overexposed when the distance to the subject is short. Since discharge tubes such as xenon tubes used for strobes emit a small amount of light, even if the light emission stop control is performed immediately after the light emission starts, the discharge does not stop immediately and continues to emit light for a predetermined time. Unusual phenomenon occurs.

For this reason, the strobe has a minimum light emission amount that can ensure accuracy in addition to the maximum light emission amount represented by a so-called guide number. In a stroboscope using a discharge tube such as a xenon tube, a light emission amount of about several hundredth of the maximum light emission amount is often the minimum light emission amount capable of guaranteeing accuracy. However, if you set the shooting sensitivity to high sensitivity and try to shoot a subject at a short distance using a flash, the exposure may be overexposed unless the flash output is lower than the minimum flash output. ..

In order to avoid such a situation, for example, it is assumed that the strobe light emission result obtained in response to the pre-light emission shows the main light emission amount that causes overexposure even if light is emitted for the minimum light emission time. In this case, there is a method in which the aperture diameter of the diaphragm is narrowed or the gain of the image signal obtained by the image sensor is reduced to obtain the main light emission amount again (see Patent Document 1).

JP-A-2002-300470

By the way, recently, there is a strobe using an LED light source as a light source. The strobe using the LED light source is inferior to the strobe using the discharge tube in the maximum light emission amount, but if the current is cut off after the light emission, the light emission is stopped in a short time. In a stroboscope using an LED light source, the minimum amount of light emission can be guaranteed with accuracy even at a fairly low level. In the future, if there will be strobes that differ not only in maximum light emission amount but also in minimum light emission amount due to differences in light sources, it will be difficult to shoot the brightness of the subject and the background in a well-balanced manner depending on the difference in performance of each strobe. Becomes

Therefore, it is an object of the present invention to provide an image pickup apparatus, a control method thereof, and a control program, which can photograph a subject and a background in a well-balanced manner in accordance with a difference in performance of each strobe.

In order to achieve the above-mentioned object, an imaging device according to the present invention is an imaging device capable of performing luminescence shooting in which a plurality of light emitting devices are selectively made to emit light to photograph a subject, and among the plurality of light emitting devices , A selection unit that selects one of a plurality of shooting conditions when shooting the subject as a selected shooting condition according to the minimum light emission amount of the light emitting device used by the image pickup device , the selected shooting condition, and the brightness of the subject. calculates the exposure of imaging a subject based, said decides whether to perform flash shooting, have a, and control means for photographing the object, said selection means, said plurality of light emitting devices Of these, the case of performing the light emission shooting using the second light emitting device whose minimum light emission amount is smaller than that of the first light emitting device is more preferable than the case of performing the light emission shooting using the first light emitting device. It is characterized in that the selected photographing condition having a high upper limit of photographing sensitivity is selected .

According to the present invention, the exposure is calculated based on the shooting condition selected according to the minimum light emission amount of the light emitting device and the brightness of the subject, and whether to emit the light is determined according to the brightness of the subject. To do. Thereby, it is possible to photograph the brightness of the subject and the background in a well-balanced manner according to the difference in performance of each light emitting device.

FIG. 3 is a cross-sectional view showing the configuration of an example of the imaging device according to the first embodiment of the present invention. It is a figure which shows the structure about an example of the sensor for focus detections shown in FIG. It is a figure which shows the photometry area|region which divided the light-receiving surface of the sensor for photometry shown in FIG. 1 into several areas. FIG. 2 is a diagram showing an example of correspondence between a field of view of a photometric sensor and a focus detection area of a focus detection sensor in a finder field of the finder optical system shown in FIG. 1. It is a figure which shows the other example of the flash attached to the camera main body shown in FIG. FIG. 3 is a block diagram for explaining an example of a control system in the camera shown in FIG. 1. 6 is a block diagram showing an example of a control system of the strobe shown in FIG. 5. FIG. 6 is a flowchart for explaining an example of shooting processing in the camera shown in FIG. 5. 9 is a flowchart for explaining the exposure calculation and flash emission determination processing shown in FIG. 8. It is a figure which shows an example of a 1st program diagram. It is a figure which shows an example of a 2nd program diagram. 9 is a flowchart for explaining an example of exposure calculation and flash emission determination processing performed by the camera of the second embodiment of the present invention.

Hereinafter, an example of the imaging device according to the embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a sectional view showing the arrangement of an example of an image pickup apparatus according to the first embodiment of the present invention.

The illustrated image pickup apparatus is, for example, a lens interchangeable single-lens reflex camera (hereinafter simply referred to as a camera), a camera body 1, an interchangeable lens unit (hereinafter simply referred to as an interchangeable lens) 2, and a strobe device (hereinafter, referred to as strobe). ) 3 and other light emitting devices. The strobe (hereinafter also referred to as a flash) 3 can be attached to and detached from the camera body 1. The strobe 3 may be built in the camera body 1.

The camera body 1 is provided with an image pickup device 12, and the image pickup device 12 is, for example, an area storage type image pickup device such as a CMOS or CCD sensor. An optical low-pass filter 11 is arranged on the front side of the image sensor 12, and a mechanical shutter 10 is arranged in front of the optical low-pass filter 11.

A semi-transparent main mirror 13 is arranged in front of the mechanical shutter 10. A first reflection mirror 14 is arranged between the mechanical shutter 10 and the main mirror 13. The main mirror 13 and the first reflecting mirror 14 jump upward in the drawing at the time of photographing. In other words, the main mirror 13 and the first reflecting mirror 14 are retracted from the optical axis of the interchangeable lens 2 during shooting.

A paraxial image forming surface 15 is defined on the optical axis of the light reflected by the first reflecting mirror 14, and this paraxial image forming surface 15 forms an image of the image pickup device 12 with respect to the first reflecting mirror 14. It is in a position conjugate with the surface.

The second reflection mirror 16 reflects the light reflected by the first reflection mirror 14 and guides it to the focus detection sensor (AF sensor) 20. An infrared cut filter 17, a diaphragm 18, and a secondary imaging lens 19 are arranged between the second reflection mirror 16 and the focus detection sensor 20. Two apertures are formed in the diaphragm 18. The focus detection sensor 20 includes, for example, an area storage type photoelectric conversion element such as a CMOS or a CCD.

FIG. 2 is a diagram showing the configuration of an example of the focus detection sensor 20 shown in FIG.

The focus detection sensor 20 has light receiving sensor units 20A and 20B respectively corresponding to the two openings of the diaphragm 18 shown in FIG. Each of the light receiving sensor units 20A and 20B is divided into a large number of light receiving units.

Further, although not shown, the focus detection sensor 20 is provided with peripheral circuits for signal storage and signal processing, and these peripheral circuits are integrated on the same chip together with the light receiving sensor units 20A and 20B.

The first reflection mirror 14, the second reflection mirror 16, the infrared cut filter 17, the diaphragm 18, the secondary imaging lens 19, and the focus detection sensor 20 are included in one configuration. With this configuration, it is possible to perform focus detection by a so-called image shift method at an arbitrary position on the shooting screen (see Japanese Patent Laid-Open No. 9-184965).

Referring again to FIG. 1, a focusing plate 21 having diffusibility is arranged above the main mirror 13, and a penta prism 22 is arranged above the focusing plate 21. Then, the light that has passed through the prism 22 enters the eyepiece lens 23.

A third reflecting mirror 24 is arranged near the prism 22, and the light reflected by the third reflecting mirror 24 is guided to a photometric sensor 26 via a condenser lens 25. The photometric sensor 26 is for obtaining brightness information indicating the brightness of the subject. The photometric sensor 26 has an area storage type photoelectric conversion element such as a CMOS or CCD.

FIG. 3 is a diagram showing a photometric area obtained by dividing the light receiving surface of the photometric sensor 26 shown in FIG. 1 into a plurality of areas.

The light-receiving surface of the photometric sensor 26 is divided into a plurality of regions to define a plurality of photometric regions. Then, the photometric sensor 26 outputs luminance information regarding the subject for each photometric area. In the illustrated example, the light receiving surface is divided into 35 photometric areas of 5 rows×7 columns, and photometric areas PD1 to PD35 are formed.

Although not shown, in the photometric sensor 26, peripheral circuits for signal amplification and signal processing are integrated on the same chip in addition to the light receiving pixel portion.

Referring again to FIG. 1, in the illustrated camera, the focusing plate 21, the pentaprism 22 and the eyepiece lens 23 form a finder optical system. A part of the light reflected by the main mirror 13 and further diffused by the focusing plate 21 enters the photometric sensor (AE sensor) 26.

FIG. 4 is a diagram showing an example of correspondence between the field of view of the photometric sensor 26 and the focus detection area of the focus detection sensor 20 in the finder field of the finder optical system shown in FIG.

As illustrated, a total of 7 areas S0 to S6 are shown as focus detection areas. These focus detection areas S0 to S6 are arranged at positions corresponding to the photometric areas PD18, PD17, PD19, PD16, PD20, PD11, and PD25, respectively.

Referring again to FIG. 1, the camera body 1 is provided with a mount portion 27 for mounting an interchangeable lens (also referred to as a taking lens) 2. A contact portion 28 for communicating with the taking lens 2 is formed on the mount portion 27.

The interchangeable lens 2 includes optical lenses 30a to 30e and a diaphragm 31. Further, the rear end surface of the interchangeable lens 2 is provided with a lens contact portion 32 for communicating with the camera body 1, and a mount portion 33 for attaching the interchangeable lens 2 to the camera body 1.

The camera body 1 is provided with a connecting portion 29 for mounting the strobe 3, and the strobe 3 is attached to the camera body 1 by connecting the attaching portion 38 provided on the strobe 3 to the connecting portion 29. The strobe 3 includes a xenon tube 34, which is a light emitting unit, a reflection shade 35, and a Fresnel lens 36 for condensing. Further, the strobe 3 has a monitor sensor 37 for monitoring the amount of light emitted by the xenon tube 34.

FIG. 5 is a diagram showing another example of a strobe attached to the camera body 1 shown in FIG.

The strobe 4 shown in the figure includes an LED light source 81 that is a light emitting unit, a reflective shade 82, and a Fresnel lens 83 for condensing, and a monitor sensor 84 for monitoring the light emission amount of the LED light source 81. Then, the strobe 4 is attached to the camera body 1 by the attaching portion 85.

FIG. 6 is a block diagram for explaining an example of a control system in the camera shown in FIG. In FIG. 6, the same components as those shown in FIG. 1 are designated by the same reference numerals.

The camera body 1 is provided with a camera control unit 41. The camera control unit 41 is, for example, a one-chip microcomputer including an arithmetic unit (ALU), a ROM, a RAM, an A/D converter, a timer (Timer), and a serial communication port (SPI). Then, the camera control unit 41 controls the entire camera.

Output signals of the focus detection sensor (AF sensor) 20 and the photometric sensor (AE sensor) 26 are input to an input terminal of an A/D converter included in the camera control unit 41.

The signal processing circuit 43 drives and controls the image sensor 12 under the control of the camera control unit 41 to set the read gain. Then, the signal processing circuit 43 A/D-converts the image signal (imaging signal) output from the image sensor 12, and then performs predetermined signal processing to obtain image data. Further, the signal processing circuit 43 performs predetermined image processing such as compression processing or composition processing when recording image data. The signal processing circuit 43 has a function of detecting a human face by extracting characteristic parts such as eyes and mouth in the image data. Further, the signal processing circuit 43 generates a display image from the image data.

The memory 44 is, for example, a DRAM, and is used as a work memory when the signal processing circuit 43 performs signal processing. Further, the memory 44 is used as a VRAM when displaying an image on the display 45.

The display device 45 is composed of, for example, a TFT liquid crystal panel or an organic EL panel, and various display information and images obtained as a result of imaging are displayed on the display device 45. Then, the camera control unit 41 controls the lighting of the display 45. The storage unit 46 is, for example, a nonvolatile memory such as a flash memory, and the signal processing circuit 43 stores image data in the storage unit 46.

As shown in the figure, a first motor driver 47, a release switch (SW) 49, a shutter drive unit 42, and a live view start switch (LVSW) 50 are connected to the camera control unit 41. The first motor driver 47 drives the first motor 48 for up/down of the main mirror 13 and the first reflection mirror 14 and charging of the mechanical shutter 10 under the control of the camera control unit 41. To do.

The shutter drive unit 42 drives the mechanical shutter 10 under the control of the camera control unit 41. The release SW 49 is a switch for instructing the camera control unit 41 to start shooting. The LVSW 50 is a switch used when starting a live view for sequentially displaying images (through images) output from the image sensor 12 on the display device 45.

The contact unit 28 provided in the camera body 1 is connected to the SPI provided in the camera control unit 41. Further, the connection unit 29 provided in the camera body 1 is connected to the SPI provided in the camera control unit 41.

The interchangeable lens 2 is provided with a lens controller 51. The lens controller 51 is, for example, a one-chip microcomputer including an ALU, ROM, RAM, timer, and SPI.

The second motor driver 52 drives the second motor 53 for focus adjustment under the control of the lens controller 51. The third motor driver 54 drives a third motor 55 for driving the diaphragm 31 under the control of the lens controller 51.

A distance detection unit (distance encoder) 56 and a zoom detection unit (zoom encoder) 57 are connected to the lens control unit 51. The distance encoder 56 obtains subject distance information indicating the amount of extension of the focus adjustment lens (that is, the focus lens), that is, the subject distance. The zoom encoder 57 obtains focal length information indicating a focal length at the time of shooting according to the movement of the zoom lens provided in the interchangeable lens 2. The lens contact unit 32 is connected to the SPI provided in the lens control unit 51.

When the interchangeable lens 2 is attached to the camera body 1, the contact portion 28 and the lens 32 are connected. As a result, the lens controller 51 can perform data communication with the camera controller 41. Then, the lens control unit 51 sends to the camera control unit 41 the lens-specific optical information, subject distance information, and focal length information necessary for performing focus detection and exposure calculation.

The camera control 41 sends focus adjustment information and aperture information obtained by focus detection and exposure calculation to the lens controller 51. The lens control unit 51 controls the second motor driver 52 according to the focus adjustment information, and controls the third motor driver 54 according to the aperture information.

The strobe 3 is provided with a strobe control unit 61. The strobe control unit 61 is, for example, a one-chip microcomputer including an ALU, a ROM, a RAM, a timer, and an SPI (both not shown). The boosting unit 62 generates a high voltage of about 300 V necessary for light emission of the xenon tube, which is the light emitting unit 34, and charges the high voltage.

When the strobe 3 is attached to the camera body 1, the strobe control unit 61 can perform data communication with the camera control unit 41 with the attachment unit 38 and the connection unit 29 connected. The data communication includes the maximum light emission amount (guide number information) and the minimum light emission amount minG that the strobe 3 can emit. The strobe control unit 61 controls the boosting unit 62 under the control of the camera control unit 41 to start and stop the light emission of the light emitting unit (xenon tube) 34. When the flash control unit 61 receives a light emission amount instruction from the camera control unit 41, the light emission unit 34 starts light emission in response to the light emission amount instruction. Then, the flash control unit 61 controls the light emitting unit 34 to stop based on the amount of light detected by the monitor sensor 37.

FIG. 7 is a block diagram showing an example of a control system of the strobe shown in FIG. In the following description, the strobe 3 is called the first strobe 3, and the strobe 4 is called the second strobe 4.

The second strobe 4 is provided with a strobe controller 91. The flash control unit 91 is, for example, a one-chip microcomputer including an ALU, a ROM, a RAM, a timer, and an SPI (both not shown). The booster 92 generates a voltage for light emission required for light emission of the LED light source 81 which is a light emitting unit.

When the second strobe 4 is attached to the camera body 1, the strobe control unit 91 can perform data communication with the camera control unit 41 with the attachment unit 85 and the connection unit 29 connected. The data communication includes the maximum light emission amount (guide number information) and the minimum light emission amount minG that can be emitted by the second strobe 4. The strobe control unit 91 controls the boosting unit 92 under the control of the camera control unit 41 to start and stop the light emission of the LED light source 81. Upon receiving the light emission amount instruction from the camera control unit 41, the strobe control unit 91 starts light emission by the LED light source 81 according to the light emission amount instruction. Then, the flash control unit 91 stops and controls the LED light source 81 based on the light amount detected by the monitor sensor 84.

FIG. 8 is a flowchart for explaining an example of shooting processing in the camera shown in FIG. The process according to the illustrated flowchart is performed under the control of the camera control unit 41.

Now, when the power switch (not shown) provided in the camera is turned on, the camera control unit 41 becomes operable. Then, the camera control unit 41 obtains strobe information (also called flash information) including the charging information and the minimum light emission information minG from the strobe control unit 61 (step S101). Subsequently, the camera control unit 41 obtains lens information necessary for distance measurement and photometry from the lens control unit 51 (step S102).

Next, the camera control unit 41 determines whether the LVSW 50 is operated, that is, whether the LVSW 50 is on (step S103). When the LVSW 50 is off (NO in step S103), the camera control unit 41 controls the focus detection sensor 20 to perform charge accumulation (signal accumulation). Then, when the signal storage ends, the camera control unit 41 reads out the signal (that is, the electric charge) stored in the focus detection sensor 20 (step S104). The camera control unit 41 A/D-converts the signal charges to obtain focus detection data, and performs data correction such as shading correction on the focus detection data.

Next, the camera control unit 41 performs focus detection for each focus detection area according to the lens information and the focus detection data to obtain a focus detection result (step S105). Then, the camera control unit 41 determines the focus detection area to be focused in the focus detection areas S0 to S6. In determining the focus detection area, for example, the camera control unit 41 determines the focus detection area designated by the user as the focus detection area to be focused. The camera control unit 41 may determine the main subject area as the focus detection area to be focused.

The camera control unit 41 calculates the amount of lens movement for achieving the in-focus state according to the focus detection result in the focus detection area to be focused. Then, the camera control unit 41 sends the lens drive amount to the lens control unit 51. The lens control unit 51 controls the second motor driver 52 based on the lens drive amount to drive the focus adjustment lens by the second motor 53 (step S105). As a result, the interchangeable lens 2 is in focus with respect to the main subject. At this time, since the subject distance information changes due to the driving of the focus adjustment lens, the lens control unit 51 updates the lens information.

Subsequently, the camera control unit 41 calculates the defocus amount (also referred to as defocus information) which is the focus detection result in the focus detection areas S0 to S6 when the interchangeable lens 2 is in focus with respect to the main subject. To do. The defocus amount for the focus detection area (distance measurement area) is DF(n). n is any integer of 0 to 6.

After that, the camera control unit 41 performs storage control and signal readout control for the photometric sensor 26 (step S106). As a result, the photometric sensor 26 accumulates charges for a predetermined time and outputs signal charges. The camera control unit 41 A/D converts the signal charge and stores it in the RAM as photometric data. Here, the camera control unit 41 reads the signal charges from the light receiving units PD1 to PD35, performs A/D conversion, and obtains luminance information. Then, the camera control unit 41 corrects the brightness information based on the lens information, and obtains the subject brightness information which is the photometric data for each light receiving unit.

Next, the camera control unit 41 performs a predetermined exposure calculation process, as described later, based on the photometric data stored in the RAM, and a determination process for determining whether or not to emit a strobe (flash) ( Flash emission determination processing) is performed (step S107).

FIG. 9 is a flowchart for explaining the exposure calculation and flash emission determination processing shown in FIG.

First, the camera control unit 41 calculates the luminance of the entire image by performing a weighting operation on the subject luminance information (photometric data) for each light receiving unit, with a focus on the focus detection area focused during focus adjustment. (Step S201). Here, this brightness is the subject brightness Bv. Then, the camera control unit 41 obtains the minimum light emission amount minG from the flash information (flash information) (step S202).

Subsequently, the camera control unit 41 compares the minimum light emission amount minG with a predetermined threshold value Gth and determines whether minG≦Gth (below the threshold value) (step S203). Since the first strobe 3 uses the xenon tube 34 in the light emitting portion, the minimum light emission amount minG is relatively large, and the minimum light emission amount minG>threshold Gth. On the other hand, in the second strobe 4, since the LED light source is used for the light emitting portion, the minimum light emission amount minG is relatively small, and the minimum light emission amount≦threshold value.

If the minimum light emission amount minG>threshold value Gth (NO in step S203), the camera control unit 41 selects the first program diagram (selective shooting condition) to obtain the exposure, and also determines the flash light emission ( Step S204).

FIG. 10 is a diagram showing an example of a first program diagram (first shooting condition).

In FIG. 10, the horizontal axis represents the subject brightness Bv, and the vertical axis represents the shutter speed TV1, the aperture value AV1, and the shooting sensitivity SV1 that are determined according to the subject brightness Bv. That is, in FIG. 10, the relationship between the subject brightness Bv, the shutter speed TV1, the aperture value AV1, and the photographing sensitivity SV1 is defined. Now, when the subject brightness Bv is 4, the photographing sensitivity SV1 is equivalent to ISO sensitivity 100. Further, the proper exposure is obtained when the shutter speed TV1 is 1/60 seconds and the aperture value AV1 is 2.8.

When the subject brightness Bv is brighter than 4, the photographing sensitivity SV1 is kept to be equivalent to ISO sensitivity 100. In this case, the shutter speed TV1 is reduced by 0.5 step each time the subject brightness Bv is increased by 1 step from 1/60 seconds, and the aperture value AV1 is decreased by 0.5 step each time the object brightness Bv is increased by 1 step from 2.8. Proper exposure is achieved. Under these conditions, flash photography (flash photography) is not performed, and photography is performed using only natural light. When the subject brightness Bv is less than 4, the shutter speed TV1 is fixed at 1/60 seconds.

As illustrated, when the subject brightness Bv is less than 4 and is 1 or more, the aperture value AV1 is fixed to 2.8. At this time, the photographing sensitivity SV1 is appropriately changed (raised) from ISO sensitivity 100 equivalent to 800 equivalent to obtain proper exposure. Even under these conditions, flash photography is not performed, and photography is performed using only natural light.

When the subject brightness Bv becomes less than 1, flash photography is performed. When the subject brightness Bv is less than 1 and is 0 or more, the photographing sensitivity SV1 is fixed to the ISO sensitivity of 800 and the aperture value AV1 is changed from 4.0 to 2.8. When the subject brightness Bv is less than 0, the aperture value AV1 is fixed at 2.8. At this time, if the subject brightness Bv is less than 0 and is -1 or more, the photographing sensitivity SV1 is changed from ISO800 to ISO1600. When the subject brightness Bv is less than -1, the photographing sensitivity SV1 is fixed to ISO1600.

When the first program diagram is used, since the minimum amount of light emitted from the strobe is high, the effect of brightly capturing a dark background such as a night view is reduced. On the other hand, the upper limit of the photographing sensitivity SV1 is set low in order to avoid overexposure with respect to the subject photographed with flash. As described above, when the photographing sensitivity, the shutter speed, and the aperture value are determined, and whether or not the stroboscopic light emission is performed is determined, the camera control unit 41 proceeds to the process of step S108 described later.

If the minimum light emission amount minG≦threshold value Gth (YES in step S203), the camera control unit 41 determines exposure using the second program diagram and determines flash light emission (step S205).

FIG. 11 is a diagram showing an example of the second program diagram (second shooting condition).

In FIG. 11, when the subject brightness Bv is 4, the photographing sensitivity SV1 is equivalent to ISO sensitivity 100. Further, the proper exposure is obtained when the shutter speed TV1 is 1/60 seconds and the aperture value AV1 is 2.8.

When the subject brightness Bv is brighter than 4, the photographing sensitivity SV1 is kept to be equivalent to ISO sensitivity 100. In this case, the shutter speed TV1 is reduced by 0.5 step each time the subject brightness Bv is increased by 1 step from 1/60 seconds, and the aperture value AV1 is decreased by 0.5 step each time the object brightness Bv is increased by 1 step from 2.8. Proper exposure is achieved. Under these conditions, flash photography (flash photography) is not performed, and photography is performed using only natural light. When the subject brightness Bv is less than 4, the shutter speed TV1 is fixed at 1/60 seconds.

As illustrated, when the subject brightness Bv is less than 4 and is 1 or more, the aperture value AV1 is fixed to 2.8. At this time, the photographing sensitivity SV1 is appropriately changed (raised) from ISO sensitivity 100 equivalent to 800 equivalent to obtain proper exposure. Even under these conditions, flash photography is not performed, and photography is performed using only natural light.

When the subject brightness Bv becomes less than 1, flash photography is performed. When the subject brightness Bv is less than 1 and is 0 or more, the photographing sensitivity SV1 is fixed to the ISO sensitivity of 800 and the aperture value AV1 is changed from 4.0 to 2.8. When the subject brightness Bv is less than 0, the aperture value AV1 is fixed at 2.8. At this time, if the subject brightness Bv is less than 0 and is -3 or more, the photographing sensitivity SV1 is appropriately changed from ISO800 to ISO6400. When the subject brightness Bv is less than -3, the photographing sensitivity SV1 is fixed to ISO6400.

When the second program diagram is used, the minimum light emission amount of the strobe is low, and therefore there is little possibility that the subject will be overexposed even if flash photography is performed with high sensitivity. Therefore, the upper limit of the photographing sensitivity SV1 is set as high as ISO6400. As a result, a dark background such as a night view can be captured together with the subject. As described above, when the photographing sensitivity, the shutter speed, and the aperture value are determined, and whether or not the stroboscopic light emission is performed is determined, the camera control unit 41 proceeds to the process of step S108 described later.

Referring again to FIG. 8, after the processing of step S107, the camera control unit 41 determines whether or not the release SW 49 has been turned on (step S108). If the release SW 49 is not turned on (NO in step S108), the camera control unit 41 returns to the process of step S102. When release SW 49 is turned on (YES in step S108), camera control unit 41 proceeds to the process of step S116 described later.

When the LVSW 50 is on (YES in step S103), the camera control unit 41 drives and controls the first motor driver 47 to flip up the main mirror 13 and the first reflecting mirror 14 (step S109).

Subsequently, the camera control unit 41 controls the shutter drive unit 42 to open the shutter 10 (step S110). As a result, an optical image enters the image sensor 12 from the interchangeable lens 2 and forms an image on the image sensor 12. Then, the camera control unit 41 processes the output of the image sensor 12 by the signal processing circuit 43 and displays an image on the display unit 45 to perform live view.

Next, the camera control unit 41 obtains the luminance information and the color information from the image data (that is, the image pickup information) obtained by the image pickup in order to make the brightness and the hue of the image during the live view proper, and then the image pickup element. 12 accumulation times and color corrections are performed. That is, the camera control unit 41 performs AE and WB control (step S111).

Subsequently, the camera control unit 41 performs a face detection process for detecting a face area in the image data (step S112). For example, as described in Japanese Unexamined Patent Application Publication No. 2005-184508, the camera control unit 41 detects the face position of a person by extracting characteristic edges of eyes and mouth from image data. Further, the camera control unit 41 detects the contour including the eyes and the mouth, obtains the position of the center of gravity, and calculates the brightness of the area within the contour. After that, the camera control unit 41 obtains face position information in the image based on the position of the center of gravity, and obtains face size information based on the contour. In the following description, the face size indicated by the face size information is FS.

Further, in step S112, the camera control unit 41 sends a lens drive command to the lens control unit 51 in order to perform focus adjustment. As a result, the lens controller 51 controls the second motor driver 52 to drive the focus adjustment lens by the second motor 53. At this time, the camera control unit 41 controls the lens control unit 51 to stop the focus adjustment lens at the position where the contrast value in the image is maximum. As a result, the interchangeable lens 2 is in focus on the subject (AF control).

Since the output of the distance detection unit (distance encoder) 56 changes by driving the focus adjustment lens, the lens control unit 51 updates the lens information. In addition, so-called face detection AF is performed to adjust the focus so that the contrast value in the face area is maximized.

Next, the camera control unit 41 performs the exposure calculation for the main shooting and the flash emission determination (step S113). The process of step S113 is similar to the process of step S107.

Subsequently, the camera control unit 41 determines whether or not the release SW 49 is turned on (step S114). If the release SW 49 is not turned on (NO in step S114), the camera control unit 41 returns to the process of step S111. When release SW 49 is turned on (YES in step S114), camera control unit 41 controls shutter drive unit 42 to close shutter 10 and ends LV. Then, the camera control unit 41 controls the first motor driver 47 to move down the main mirror 13 and the first reflecting mirror 14 by the first motor 48 and charge the mechanical shutter 10 (step S115).

Next, the camera control unit 41 determines whether it is determined in step S107 or S113 that the strobe (flash) is to be emitted (step S116). When it is determined that the strobe light is to be emitted (YES in step S116), the camera control unit 41 performs the photometry immediately before the pre-emission and also performs the photometry by the pre-emission (step S117).

In the process of step S117, the camera control unit 41 reads the signal charges of the light receiving units PD1 to PD35, performs A/D conversion, and obtains the brightness information immediately before the preliminary light emission as the brightness information P(i) before the preliminary light emission. Note that i=1 to 35 is an integer.

Subsequently, the camera control unit 41 causes the flash control unit 61 to pre-flash the strobe. Then, the flash control unit 61 controls the light emission of the light emitting unit 34 based on the output of the light emission monitor unit so that the light emitting unit 34 emits light with a predetermined preliminary light emission amount. The camera control unit 41 reads out the signal charges of the light receiving units PD1 to PD35, performs A/D conversion, and obtains luminance information at the time of preliminary light emission as luminance information at the time of preliminary light emission H(i).

Next, the camera control unit 41 obtains the main light emission amount (main light emission gain) of the strobe at the time of shooting (step S118). A method for obtaining the main light emission amount based on the pre-preliminary light emission luminance information P(i) and the pre-light emission luminance information H(i) is described in, for example, JP-A-2005-275265. Therefore, the description is omitted here.

Subsequently, the camera control unit 41 controls the first motor driver 47 to cause the first motor 48 to flip up the main mirror 13 and the first reflecting mirror 14. Then, the camera control unit 41 sends the aperture value obtained in step S107 or S113 to the lens control unit 51. The lens controller 51 controls the third motor driver 54 based on the aperture value to drive the aperture 31 by the third motor 55 (step S119). As a result, the interchangeable lens 2 is brought into a narrowed state.

Next, the camera control unit 41 controls the shutter drive unit 42 to open the shutter 10. As a result, an optical image is formed on the image sensor 12 via the interchangeable lens 2. Then, the camera control unit 41 controls the signal processing circuit 43 based on the accumulation time according to the shutter speed (that is, the shutter opening time) obtained in step S107 or S113 described above and the read gain according to the imaging sensitivity. (Step S120). As a result, signal accumulation is performed in the image sensor 12. That is, imaging is performed.

At this time, when performing flash photography, the camera control unit 41 sends a strobe light emission instruction to the strobe control unit 61 in synchronization with the image capturing timing. As a result, the strobe control unit 61 causes the light emitting unit 34 to emit the main light emission amount while monitoring the output of the light emission monitor unit 37 based on the strobe light emission instruction. As a result, imaging with flash light emission is performed.

When the image capturing is completed, the camera control unit 41 controls the shutter drive unit 42 to bring the shutter 10 into the light blocking state. This shields the image sensor 12 from light. After that, the camera control unit 41 instructs the lens control unit 51 to open the diaphragm 31. Then, the lens controller 51 controls the third motor driver 54 to drive the diaphragm 31 by the third motor 55 (step S121). As a result, the interchangeable lens 2 is in the aperture open state. Further, in step S121, the camera control unit 41 controls the first motor driver 47 so that the first motor 48 causes the main mirror 13 and the first reflecting mirror 14 to move down.

Subsequently, the camera control unit 41 performs A/D conversion of the image signal output from the image sensor 12 by the signal processing circuit 43, and then performs predetermined correction processing and interpolation processing (step S122). Further, the camera control unit 41 performs white balance processing by the signal processing circuit 43 (step S123). In the process of step S123, the signal processing circuit 43 divides the entire image data (one screen) acquired under the control of the camera control unit 41 into a plurality of regions, and the white color of the subject is calculated based on the color difference signal for each region. Extract a region. Then, the signal processing circuit 43 adjusts the white balance by performing gain correction of the red channel and the blue channel of the entire image data based on the white area.

Next, the camera control unit 41 compresses and converts the image data after the white balance processing into a recording file format, and then stores it in the storage unit 46. Then, the camera control unit 41 ends the shooting process.

As described above, in the first embodiment of the present invention, the program charts having different upper limits of the photographing sensitivity are switched according to the minimum light emission amount of the strobe attached to the camera body. This can reduce the frequency of overexposure of the subject during flash photography in a strobe with a large minimum light emission amount. On the other hand, in the case of a strobe having a small minimum light emission amount, it is possible to avoid overexposure of the subject at the time of stroboscopic photography and photograph a background brighter.

Note that the switching between the first and second program charts described in the first embodiment is an example, and three or more program charts are used to selectively use these program charts according to these strobes. You may do it. Furthermore, the setting of the shutter speed, the aperture value, and the shooting sensitivity according to the brightness of the subject, and the determination of whether or not to perform the flash shooting are also examples. Further, the minimum light emission amount of the auxiliary photographing light source such as a strobe mainly differs depending on the type of the light emitting source. Therefore, information indicating the type of light emitting source may be used instead of the information indicating the minimum light emission amount. For example, in the processing of steps S202 and S203 described above, the camera control unit 41 selects the first program diagram according to the type of the light emission source based on the information indicating the type of the light emission source, or the second program. The configuration may be such that the selection of the diagram is switched.

[Second Embodiment]
Next, an example of a camera according to the second embodiment of the present invention will be described. The configuration of the camera according to the second embodiment is similar to that of the camera described in the first embodiment. The shooting process in the camera according to the second embodiment is the same as the shooting process described in FIG. 8, but the exposure calculation and the flash emission determination process are different.

In the above-described first embodiment, the program diagram is switched based on the minimum light emission amount of the strobe attached to the camera body. However, there is a high possibility that the subject will be overexposed by flash photography when the subject is located at a short distance from the camera. Therefore, in the second embodiment, the program diagram is switched according to the minimum flash emission amount and the position of the subject.

FIG. 12 is a flowchart for explaining an example of exposure calculation and flash emission determination processing performed by the camera of the second embodiment of the present invention. Note that the processing of steps S301 to S303, S306, and S307 shown is the same as the processing of steps S201 to S205 shown in FIG.

In the process of step S303, if the minimum light emission amount minG>threshold value Gth (NO in step S203), the camera control unit 41 obtains the distance information and the focal length information from the lens control unit, and the face size information FS. Get (step S304). The output of the distance detection unit 56 is used as the distance information, and the output of the zoom detection unit 57 is used as the focal length information.

Subsequently, the camera control unit 41 determines whether or not short-distance shooting is performed using at least one of the distance information, the focal length information, and the face size information FS (step S305). Here, when the subject distance indicated by the distance information is equal to or less than the predetermined distance, the camera control unit 41 determines that the short distance shooting is performed. If there is no distance information, the camera control unit 41 estimates the subject distance based on the face size information FS and the focal length information. Then, when the subject distance is equal to or shorter than the predetermined distance, the camera control unit 41 determines that the short distance shooting is performed.

In addition, in the present embodiment, the above-mentioned predetermined distance is set to 3 m, but the present invention is not limited to this, and other distance may be set.

When it is determined that the close-up shooting is performed (YES in step S305), the camera control unit 41 proceeds to the process of step S306. On the other hand, when it is determined that the close-range shooting is not performed (NO in step S305), the camera control unit 41 proceeds to the process of step S307.

In the second embodiment, minG>Gth, and the first program diagram is used in the case of short-distance photography. That is, in the case of minG>Gth, and in the case of short-distance shooting, if the shooting sensitivity is increased, the subject becomes overexposed. In order to prevent such a situation, the photographing sensitivity, the shutter speed, the aperture value, and the presence/absence of flash emission are determined using the first program diagram in which the upper limit value of the photographing sensitivity SV1 is set low.

On the other hand, when minG≦Gth or when the short-distance shooting is not performed, the second program diagram is used. That is, when minG≦Gth or when the short-distance shooting is not performed, it is unlikely that the subject is overexposed even if the shooting sensitivity is high. For this reason. The shutter speed, the aperture value, and the presence/absence of flash emission are determined by using the second program diagram in which the upper limit value of the photographing sensitivity SV1 is set high.

As is clear from the above description, in the example shown in FIG. 6, the camera control unit 41 functions as a selection unit and a control unit.

Although the present invention has been described above based on the embodiments, the present invention is not limited to these embodiments, and various embodiments within the scope not departing from the gist of the present invention are also included in the present invention. ..

For example, in the above embodiment, the camera body 1 and the interchangeable lens 2 are separately provided, but they may be integrally provided. Further, one or both of the strobe 3 and the strobe 4 may be built in the camera body 1. When the above-mentioned configuration is adopted, control of the interchangeable lens 2, the flash 3, and the flash 4 may be performed by the camera control unit 41.

Further, the functions of the above-described embodiments may be used as a control method, and the imaging apparatus may be caused to execute this control method. Alternatively, the program having the functions of the above-described embodiments may be used as a control program, and the control program may be executed by a computer included in the imaging apparatus. The control program is recorded in, for example, a computer-readable recording medium.

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

1 Camera body 2 Interchangeable lens 3,4 Strobe (flash)
12 image sensor 20 focus detection sensor 26 photometric sensor 41 camera control unit 43 signal processing circuit 61, 91 strobe control unit

Claims (6)

An imaging device capable of emitting light to shoot a subject by selectively emitting light from a plurality of light emitting devices,
Of the plurality of light emitting devices , a selection unit that selects one of a plurality of shooting conditions when shooting the subject as a selected shooting condition according to a minimum light emission amount of the light emitting device used by the imaging device ,
A control unit that calculates an exposure when a subject is imaged based on the selected photographing condition and the brightness of the subject, determines whether or not to perform the light emission photographing, and photographs the subject.
Have a,
The selecting means uses, of the plurality of light emitting devices, a second light emitting device whose minimum light emission amount is smaller than that of the first light emitting device as compared with the case where the first light emitting device is used to perform the light emission photographing. An image pickup apparatus, characterized in that, in the case of performing the light emission photographing, the selected photographing condition having a higher upper limit of photographing sensitivity is selected . The image pickup apparatus according to claim 1, wherein the shooting condition defines a relationship among the brightness of the subject, the shutter speed, the aperture value, and the shooting sensitivity. It said selecting means, among the plurality of light emitting devices, in the case of performing the light emission taken using the first light emitting device, towards the case where the distance between the imaging device and the object is less than the predetermined distance 3. The image pickup device according to claim 1, wherein the selected image pickup condition is selected such that the upper limit of image pickup sensitivity is lower than when the distance between the image pickup device and the subject is larger than a predetermined distance. apparatus. Any one of the plurality of light emitting devices is attachable to and detachable from the imaging device, and when the light emitting device is attached to the imaging device, the information about the minimum light emission amount is sent from the light emitting device to the imaging device. the imaging apparatus according to any one of claims 1 to 3, characterized in that it is. A method for controlling an image pickup device capable of performing light emission shooting , in which a plurality of light emitting devices are selectively emitted to shoot an object,
Of the plurality of light emitting devices , a selection step of selecting one of a plurality of shooting conditions when shooting the subject as a selected shooting condition according to a minimum light emission amount in the light emitting device used by the imaging device ,
A control step of calculating an exposure when capturing an image of a subject based on the selected image capturing condition and the brightness of the subject, determining whether or not to perform the light emission capturing, and capturing the subject,
Have a,
In the selecting step, of the plurality of light emitting devices, a second light emitting device whose minimum light emission amount is smaller than that of the first light emitting device is used as compared with the case where the first light emitting device is used to perform the light emission photographing. A control method, characterized in that, in the case of performing the light emission photographing, the selected photographing condition having a higher upper limit of photographing sensitivity is selected . A control program used in an imaging device capable of emitting light to shoot a subject by selectively emitting light from a plurality of light emitting devices,
In the computer included in the imaging device,
Of the plurality of light emitting devices , a selection step of selecting one of a plurality of shooting conditions when shooting the subject as a selected shooting condition according to a minimum light emission amount in the light emitting device used by the imaging device ,
A control step of calculating an exposure when capturing an image of a subject based on the selected image capturing condition and the brightness of the subject, determining whether or not to perform the light emission capturing, and capturing the subject,
Was executed,
In the selecting step, of the plurality of light emitting devices, a second light emitting device whose minimum light emission amount is smaller than that of the first light emitting device is used as compared with the case where the first light emitting device is used to perform the light emission photographing. A control program for selecting the selected photographing condition having a higher upper limit of photographing sensitivity when performing the light emission photographing .

Images