JP6398315B2 - Imaging device - Google Patents

Description

  The present invention relates to a photographing apparatus that controls preflash and main flash of a flash device.

  2. Description of the Related Art Conventionally, in photographing with a camera, flash photography in which a flash (flash device) is used for photographing in order to compensate for a shortage of light in a dark environment is generally used. As a means for determining the flash light emission amount, a pre-light emission modulation method is known in which pre-light emission is performed before photographing and the reflected light from the subject is measured, and the light emission amount of the main light emission is determined based on the measurement result.

  However, when pre-light emission is performed on a subject at the same distance, a photometric result is low for a subject with low reflectivity, and a photometric result is high for a subject with high reflectivity. For this reason, there is a problem that it is difficult to obtain proper exposure for subjects with low reflectivity because the main flash amount is set large and overexposure tends to occur, and for subjects with high reflectivity, the main flash amount is set small and underexposure tends to occur. It was.

  Patent Document 1 is provided with a photometric means for obtaining a photometric value for each of a plurality of photometric areas for the purpose of providing an imaging device capable of performing optimal flash emission control, and the accuracy of pre-emission photometric value, subject distance information, And a photometry area to be used for calculating the main flash quantity based on the appropriate photometry level calculated based on the subject distance information, and if the number of selected photometry areas is larger than a predetermined number, the photometry area is used based on the pre-flash photometry value. A pre-light emission method is disclosed in which the light emission amount is determined, and when the number of selected photometry areas is smaller than a predetermined number, the main light emission amount is determined based on the appropriate photometry level.

JP 2004-258430 A

  However, in the pre-light emission method of Patent Document 1, overexposure or underexposure can be reduced for a low-reflectance subject or a high-reflectance subject, but it is affected by the luminance of a subject that is not a priority subject. The problem that proper exposure may not be achieved has not been solved.

  An object of the present invention is to provide a photographing apparatus capable of photographing a subject with a low reflectance or a subject with a high reflectance with a proper exposure with a proper amount of light emission in pre-flash light control flash photography.

In the present invention, as a result of the AF operation, the pre-emission photometry result of the region including the focused subject and the region near the front and rear of the region is obtained when the focused subject has the standard reflectance. This is made by paying attention to the fact that correction should be made so as to approach the theoretical pre-emission photometry result. That is, the present invention relates to a flash device, focus adjusting means for focusing on a subject in one of a plurality of ranging areas, and determining a focusing state for the subjects in the plurality of ranging areas. An in-focus state determination means, a subject distance calculation means for calculating the distance of the subject in the distance measurement area focused by the focus adjustment means, and the flash device for a plurality of light measurement areas before the actual photographing. A pre-flash metering means for detecting a pre-flash photometric value based on only pre-flash from a pre-flash metering value when the pre-flash is emitted and a subject at a distance calculated by the subject distance calculating means, Corresponds to a target metering value calculating means for calculating a target metering value obtained by pre-flashing the flash device when the subject is a standard subject, and a distance measuring area determined to be in focus by the focusing state determining means. Photometry A pre-light metering value of the pre-flash metering means in the area is corrected based on the target metering value of the target metering value calculating means to obtain a corrected metering value, and corrected by the metering value correcting means And a main light emission amount setting means for setting a main light emission amount by the flash device based on the corrected photometric value, and a light measurement area corresponding to the distance measurement area determined to be in focus by the focus state determination means. When the pre-flash photometric value is Y, the target photometric value is Yref, and the photometric value corrected by the photometric value correcting unit is Y ′, the photometric value correcting unit sets the corrected photometric value Y ′ to the following formula (1) , (2) and (3) .
Y '= Yref ... (1)
(However, Yref−A ≦ Y ≦ Yref + B)
Y ′ = Y−B (2)
(However, Yref + B <Y)
Y '= Y + A (3)
(However, Y <Yref-A)
However, the pre-flash photometric value Y, the target photometric value Yref, and the corrected photometric value Y ′ are apex display brightness values, and the constants A and B are positive apex display exposure values EV.

  Further comprising a photometric area classification means for classifying the photometric area into one of a focused area, a semi-focused area, and a non-focused area according to the focused state determined by the focused state determining means; The means weights each of the photometric values in the in-focus area, the semi-in-focus area, and the out-of-focus area in order of lightening in the order of the in-focus area, the semi-in-focus area, and the out-of-focus area, thereby correcting all the photometry areas. It is preferable to calculate a post-photometric value.

  The photographing apparatus of the present invention further includes a photographing optical system including a focusing lens group that moves in the optical axis direction to adjust the focus, and a lens position detection unit that detects a position of the focusing lens group in the optical axis direction. In this case, the focus adjusting unit detects the phase difference between the pair of subject images by dividing the subject light flux that has passed through the photographing optical system into different distance measurement areas, and detects the phase difference. Based on this, a focus position of the focus lens group is detected, the focus lens group is moved to the detected focus position, and the subject distance calculation unit is configured to detect the focus position from the lens position detected by the lens position detection unit. The distance of the subject in the distance measurement area focused by the focus adjustment unit is calculated, and the focus state determination unit calculates the defocus amount from the phase difference between the pair of subject images for each distance measurement region. Def Determining an in-focus state based on carcass weight.

  It is practical that a luminance sensor that receives a subject light flux passing through the photographing optical system and measures the light for each of a plurality of photometric areas is provided, and the distance measuring area overlaps with the photometric area.

  In the photographing apparatus of the present invention, the photographing optical system provided with the focusing lens group that moves in the optical axis direction to adjust the focus, and the optical image formed by the photographing optical system at the time of the photographing are electrically An image sensor that converts to an image signal, a memory unit that records the image signal, and a brightness sensor that detects the brightness of an optical image formed by the photographing optical system can be provided separately from the image sensor. In this case, the pre-light metering means detects the pre-light metering value and the steady light metering value based on the luminance signal imaged by the luminance sensor.

  The focus adjusting unit detects the in-focus state by detecting the in-focus state based on the image signals in the plurality of distance measuring areas captured by the image sensor while moving the focusing lens group in the optical axis direction. In this case, it is practical to move the focus lens group to the position in the optical axis direction where the in-focus state is obtained.

  According to the present invention, in pre-flash light control flash photography, for a region focused as a result of AF operation, the pre-flash photometry result of that region is the theory when the subject of standard reflectance is at the focus position. Correction is made so that it approaches a specific metering value, and the metering value is calculated by placing emphasis on the metering value in that area, so it is possible to determine the appropriate main flash amount even for subjects with low or high reflectivity. it can.

It is a block diagram which shows the main optical and mechanical components about embodiment of the digital single-lens reflex camera to which the imaging device of this invention is applied. It is a figure which shows the embodiment of the main electric components of the digital single-lens reflex camera with a block. 2A and 2B are diagrams illustrating an example of a shooting screen shot by the digital single-lens reflex camera, in which FIG. 1A illustrates a relationship between a subject and a photometry area, and FIG. 2B illustrates a photometry area including a priority subject in the shooting screen. It is a figure which classify | categorizes and shows an in-focus area | region, a semi-focus area | region, and a non-focus area | region. It is a figure which shows the relationship between the photometry value and the correction value which carried out the pre light measurement with the digital single-lens reflex camera in a graph. It is a figure which shows the flash imaging | photography operation | movement of the pre light emission light control system of the digital single-lens reflex camera with a flowchart. It is a figure which shows the imaging | photography screen of the 2nd imaging | photography scene image | photographed with the same digital single-lens reflex camera, Comprising: (A) is a figure explaining the relationship between the to-be-photographed object and photometry area | region in an imaging | photography screen, (B) is the imaging | photography screen, It is a figure which shows the focus area | region, semi-focus area | region, and non-focus area | region in the photometry area | region where a priority subject is included. FIG. 7 is a diagram illustrating an example of a shooting screen of a third shooting scene shot by the digital single-lens reflex camera, where (A) illustrates the relationship between the subject and the photometry area on the shooting screen, and (B) illustrates the shooting screen. FIG. 3 is a diagram showing a focus area, a semi-focus area, and a non-focus area in a photometry area including a priority subject. It is a figure which shows the example of the imaging | photography screen of the 4th imaging scene image | photographed with the digital single-lens reflex camera, Comprising: (A) is a figure explaining the relationship between the to-be-photographed object and photometry area | region in an imaging | photography screen, (B) is the imaging | photography screen. FIG. 3 is a diagram showing a focus area, a semi-focus area, and a non-focus area in a photometry area including a priority subject.

  FIG. 1 shows an embodiment in which the present invention is applied to an interchangeable lens digital single-lens reflex camera, and its main optical elements, mechanical elements, and electronic elements are shown as blocks. The digital single lens reflex camera 10 includes a camera body 11 and a photographing lens 101 that is detachably attached to the camera body 11.

  This camera body 11 has an observation position for reflecting the subject luminous flux incident through the zoom lens group L1 and the focus lens group L2 constituting the photographing optical system of the photographing lens 101 toward the finder optical system 15, and imaging. A quick return type mirror device 14 having a main mirror 12 that moves to an imaging position to be incident on the element 31 and a mirror motor 13 that drives the main mirror 12 to an observation position and an imaging position is provided. The subject light beam reflected by the main mirror 12 at the observation position passes through the focusing screen 15a of the finder optical system 15 and enters the penta prism 16, and is reflected by the roof reflection surface 16a and the front reflection surface 16b of the penta prism 16. Inject from the eyepiece 17. The subject light beam reflected by the front reflecting surface 16b of the pentaprism 16 is incident on a luminance sensor (photometric sensor) 33 and used for divided photometry.

  Of the subject light incident on the camera body 11 through the lens groups L1 and L2 of the photographing lens 101, the subject light transmitted through the half mirror part of the main mirror 12 at the observation position and reflected by the sub mirror 12a is divided into pupils. Is incident on a distance measuring sensor 18 (phase difference AF unit). The distance measuring sensor 18 includes a pair of line sensors for each of a plurality of distance measuring areas. The subject light incident on the distance measuring sensor 18 is divided into pupils for each of the plurality of distance measuring areas, and the pair of subject lights divided into pupils is incident on the corresponding pair of line sensors, and is converted into a pair of image signals. The phase difference AF for detecting the phase difference is used, and the defocus amount and the in-focus state with respect to the subject in the corresponding distance measurement area are detected from the phase difference between the pair of image signals.

  The focus adjusting means 50a of the controller 50 moves the focus lens group L2 to the in-focus position where the detected defocus amount is 0 via the AF drive circuit 24 and the AF motor 21. The AF operation includes the above defocus amount calculation operation and the lens driving operation for moving the focusing lens unit L2 to the in-focus position.

  When the main mirror 12 is driven to the photographing position and the shutter device 20 is operated so that the shutter curtain 19 opens the shutter opening, the subject light that has passed through the shutter opening enters the image sensor 31. The shutter device 20 is a focal plane shutter having a front curtain and a rear curtain that run up and down as a shutter curtain 19 that opens and closes a shutter opening. Although not shown in detail, the shutter device 20 has a shutter drive spring for driving the front curtain and the rear curtain of the shutter curtain 19, and a front curtain and a rear curtain in an initial position where the shutter opening is closed by a charged shutter drive spring. A mechanism that mechanically locks the running, a magnet that electromagnetically locks the front curtain and rear curtain instead of the locking mechanism, and a shutter drive spring are charged, and the front curtain and rear curtain are initially It has a charge motor that moves it to the position.

  On the back surface of the camera body 11, a display 23 for displaying shooting information and a shot image is provided. Although not shown, the light emitting part of the built-in flash device (flash device) 40 is accommodated in the upper part of the pentaprism 16. The light emitting unit is configured to pop up above the pentaprism 16 when flash photography is performed. An external flash device (flash device) 41 is detachably mounted on the camera body 11 via an accessory shoe provided on the upper surface of the camera body 11 or on the bottom surface of the camera body 11 via a bracket.

  The zoom lens group L1 and the focus lens group L2 of the photographing lens 101 are lens groups that have a zoom function and a focus adjustment function. The zoom lens unit L1 is driven back and forth in the optical axis direction by a zoom operation mechanism (not shown) to perform zooming (magnification). The focusing lens group L2 is driven forward and backward in the optical axis direction along the optical axis O of the photographing lens 101 by the AF motor 21 of the camera body 11 via the link mechanism 21a to perform focus adjustment. The photographing lens 101 includes an aperture stop for adjusting the light amount and a variable aperture device 103. The aperture device 103 is driven in the opening / closing direction by the aperture motor 22 of the camera body 11 via the aperture link mechanism 22a.

  FIG. 2 is a block diagram showing an embodiment of an electrical main circuit configuration built in the camera body 11. The controller 50 comprehensively controls mechanical and electrical operations of the entire camera based on a control program recorded in a ROM (EEPROM) 51, and performs an automatic focus adjustment operation, a flash light emission operation, a photographing operation, and the like. To control.

  The image sensor 31 is an image sensor such as a CCD or CMOS. The image pickup device drive / signal processing circuit 32 takes in an image signal obtained by image pickup drive of the image pickup device 31, performs correlated double sampling, gain control, white balance adjustment, A / D conversion and the like digitized image A signal is output to the controller 50. The controller 50 converts the input image signal into a predetermined image format, temporarily writes it in the SDRAM 52, writes it in the flash memory 53, and displays it on the display 23.

  The luminance sensor 33 is an RGB color image sensor specialized in photometry that is disposed at a position for receiving subject light emitted from the pentaprism 16 (FIG. 1) and detects the luminance of a plurality of photometric areas. A subject image similar to the subject image projected onto the image sensor 31 is projected onto the luminance sensor 33. The luminance sensor 33 has the same basic configuration as that of the image sensor 31, and the shooting range is the same as or narrower than the shooting range of the image sensor 31, and the total number of pixels is smaller than that of the image sensor 31.

  The brightness sensor drive / signal processing circuit 34 captures and drives the brightness sensor 33 to capture an image signal, performs correlated double sampling, gain control, A / D conversion, and the like, and digitizes the image. Output a signal. The controller 50 periodically captures an image signal picked up by the luminance sensor 33 via the luminance sensor drive / signal processing circuit 34 during the photographing standby state, writes the image signal in the SDRAM 52, and uses the image signal of each photometric area to subject The brightness is calculated. Here, the controller 50 functions as subject luminance calculation means. FIG. 3 shows an embodiment of the photometric area on the shooting screen for shooting the first shooting scene. The luminance sensor 33 of the illustrated embodiment divides the shooting screen into 15 × 15 photometric areas (blocks) and calculates subject luminance for each photometric area. The luminance sensor drive / signal processing circuit 34 adjusts the exposure time by electronic shutter operation so that the luminance sensor 33 performs proper exposure, and performs gain control. The photometric area is not limited to this number of divisions and vertical and horizontal division ratios.

  The controller 50 includes an AF drive circuit 24 that drives the AF motor 21, an aperture drive circuit 25 that drives and controls the aperture motor 22, a shutter drive circuit 26 that drives and controls the shutter device 20, and a mirror drive circuit that drives and controls the mirror motor 13. 27 is connected. The controller 50 drives and controls the AF motor 21, the aperture motor 22, the shutter device 20, and the mirror motor 13 through the AF drive circuit 24, the aperture drive circuit 25, the shutter drive circuit 26, and the mirror drive circuit 27.

  An AF / photometry switch 35, a release switch 36, a mode selection switch 37, and a main switch 38 are connected to the controller 50 as switch means. The AF / photometry switch 35 is a switch for instructing the start of automatic focus adjustment and photometry, and the release switch 36 is a switch for instructing the start of shooting to record (write) exposure, image pickup, and the taken image signal in the flash memory 53, The mode selection switch 37 is an operation switch for operating a change or selection of a shooting mode such as a flash shooting mode for shooting with a flash and a flash prohibited shooting mode for shooting with a flash prohibited. The controller 50 performs on / off control of the power supply in accordance with on / off of the main switch 38.

  The focus adjustment means 50a of the controller 50 inputs a pair of image signals for each of a plurality of distance measurement areas from the distance measurement sensor 18, calculates a defocus amount from the phase difference between the pair of image signals, and calculates the calculated defocus amount. Then, the AF motor 21 is driven via the AF driving circuit 24, and the focusing lens group L2 is moved to the in-focus position where the defocus amount becomes zero. Thereafter, the focus state determination unit 50b of the controller 50 determines the focus state for each distance measurement area of the distance measurement sensor 18. In the example of FIG. 3B, it is assumed that the shooting screen 61 is divided into 15 × 15 distance measurement areas, and the distance measurement area and the photometry area match.

  The photographic lens 101 has a focal point determined by a subject distance or photographing distance (hereinafter referred to as “subject distance”) determined by the position of the focusing lens group L2 in the optical axis direction and a position of the zoom lens group L1 in the optical axis direction. A distance detecting means 105 for detecting the distance is provided. The distance detection unit 105 communicates the detected distance information of the subject distance and the focal length to the controller 50 of the camera body 11. The subject distance calculation unit 50 c of the controller 50 calculates the subject distance based on the distance information input from the distance detection unit 105. Although not shown, the photographic lens 101 is a memory unit that stores data unique to the photographic lens 101 such as an open aperture value and minimum aperture value information of the aperture device 103, and a communication unit that communicates these unique data and distance information to the controller 50. And has a communication function.

  The camera body 11 has a built-in flash device 40 (built-in), and an external flash device 41 is detachable via an accessory shoe or the like. The controller 50 performs flash communication with the built-in flash device 40 to cause the built-in flash device 40 to start charge for light emission, light emission amount data such as pre (preliminary) light emission amount, main light emission amount, and light emission that starts pre-light emission and main light emission. A signal, a light emission stop (quenching) signal that stops light emission, and the like are transmitted, and a charge completion signal, a light emission end signal, and the like are received from the built-in flash device 40, and the light emission of the built-in flash device 40 is controlled. Flash data such as a guide number and irradiation angle information of the built-in flash device 40 is written in the flash ROM 51 in advance. The controller 50 also performs flash communication with the attached external flash device 41 to cause the external flash device 41 to start emission charge, pre-emission amount, emission amount data such as main emission amount, pre-emission, and main emission. Sends a light emission signal, a light emission stop (quenching) signal to stop light emission, etc., and receives flash data such as a guide number and irradiation angle information, a charge completion signal, a light emission end signal, etc. from the external flash device 41, and an external flash The light emission of the device 41 is controlled.

  The controller 50 has a flash shooting mode in which the flash device 40 and the external flash device 41 are pre-flashed before performing the main flash operation, and then the main flash operation is performed to perform the main shooting. Note that the actual photographing refers to a photographing operation in which the image pickup device 31 performs an image pickup operation and records the picked up image signal in the flash memory 53. When shooting in the flash shooting mode, the controller 50 outputs the image signal obtained by the pre-flash shooting operation in which the built-in flash device 40 or the external flash device 41 is pre-flashed (preliminary flash) from the brightness sensor 33 before the main shooting. Then, an image signal obtained by a steady light photographing operation in which pre-light emission is not performed under the same exposure conditions as in pre-light emission is input. Thus, the pre-light metering means 50d of the controller 50 detects the pre-light metering value and the steady light metering value without pre-lighting.

The single-lens reflex camera 10 of the present invention includes a built-in flash device 40 or an external flash device 41 as a flash device . The controller 50 includes a focus adjusting unit 50a for focusing on a subject in any one of the plurality of ranging areas, and an in-focus state determination for determining the in-focus state for the subjects in the plurality of ranging areas. Means 50b, subject distance calculation means 50c for calculating the distance of the subject in the distance measurement area focused by the focus adjustment means, and the built-in flash device 40 or the external flash device for the plurality of photometry areas before the actual photographing. A pre-emission photometric unit 50d for detecting pre-emission photometric values based only on pre-emission and a subject distance calculation unit 50c are calculated from a pre-emission photometric value when the pre-emission 41 is pre-emission and a stationary light photometry value when the pre-emission is not performed. The target photometric value obtained by pre-flashing the built-in flash device 40 or the external flash device 41 when the subject at the specified distance is a standard subject is calculated. The target light metering value calculation means 50e and the pre-light metering value of the pre-light metering means in the light metering area corresponding to the distance measuring area determined to be in focus by the focus state determination means 50b are obtained by the target metering value calculation means 50e. wherein the target photometric value obtained Ru photometric value correcting means the corrected photometric value is corrected based on 50f, based on the photometric value correcting means corrected photometric value corrected by 50f, built-in flash device 40 or the external flash unit A function as main light emission amount setting means 50g for determining the main light emission amount by 41 is incorporated.

  The controller 50 moves the focusing lens unit L2 to the in-focus position by the focus adjusting unit 50a before the pre-flash photometry, and the in-focus state, the semi-in-focus state, and the out-of-focus state for each distance measurement area by the in-focus state determining unit 50b. , And the distance to the subject in the distance measurement area in focus is calculated by the subject distance calculation means 50c.

  The pre-flash photometric means 50d calculates a pre-flash photometric value obtained from the amount of pre-flash only from the difference between the pre-flash photometric value and the steady-light photometric value. Pre-emission is performed with a light emission amount / exposure value that provides proper exposure at the distance of the in-focus position, with the subject in the focus detection area in focus as the priority subject (main subject). Here, the appropriate exposure is a light emission amount / exposure value at which a subject with standard reflectance has appropriate brightness. The standard reflectance object generally uses a gray chart with 18% reflection. The light emission amount of the pre-light emission is controlled in accordance with the guide number of each model within a range of 1% to 20% of the maximum light emission amount in the main light emission so that a predetermined guide number is obtained.

  The target photometric value calculation means 50e of the controller 50 sets the pre-flash photometric value Y of the photometry area corresponding to the distance measurement area determined to be in focus as the subject distance based on the subject distance information of the distance measurement area. A photometric value that is theoretically obtained when there is a subject with reflectance is calculated as a target photometric value Yref. The photometric value correction means 50f corrects the pre-flash photometric value Y so as to approach the target photometric value Yref. The weighting means 50i of the controller 50 weights the photometric value in the photometric area corresponding to the distance measuring area determined to be in the focused state with the pre-flash photometric value corrected, and the total photometric result (average subject) (Luminance) is calculated, and an appropriate main light emission amount and exposure value are calculated based on the calculated photometric result.

Since the pre-flash is emitted so that the focused subject (subject located at the in-focus distance) is properly exposed, the pre-flash metering value when pre-flash is used is that the subject located at the in-focus distance has the standard reflectance. In this case, the standard target photometric value Yref is obtained. Actually, since the reflectance of the subject varies, the pre-flash photometric value is larger or smaller than the target photometric value Yref. In the present embodiment, the pre-flash photometric value before correction is Y, the post-correction photometric value after correction is Y ′, and the post-correction photometric value Y ′ is expressed by the following equations (1), (2), (3). The pre-flash photometric value Y in the calculated and focused range-finding area is corrected so as to approach the corrected target photometric value Yref.
Y '= Yref (1)
(However, Yref−A ≦ Y ≦ Yref + B)
Y ′ = Y−B (2)
(However, Yref + B <Y)
Y '= Y + A (3)
(However, Y <Yref-A)
However, the pre-flash photometric value Y, the target photometric value Yref, and the corrected photometric value Y ′ are apex display brightness values, and the constants A and B are positive apex display exposure values EV.

FIG. 4 is a graph showing an embodiment in which A = B = 2. In the graph, the horizontal axis represents the pre-flash photometric value Y, and the vertical axis represents the corrected photometric value Y ′. In this embodiment, the following correction is performed according to the magnitude of the pre-flash photometric value Y.
When the pre-flash photometric value Y is within the target photometric value Yref ± 2 EV, the target photometric value Yref is set as a corrected photometric value Y ′ (Equation (1)). With this correction, subjects whose reflectivity is close to the standard reflectivity are corrected to the target photometric value Yref of the subject with the standard reflectivity. Is done.
When the pre-flash photometric value Y is larger than the target photometric value Yref + 2EV, a value obtained by subtracting 2EV from the pre-flash photometric value Y is set as a corrected photometric value Y ′ (Equation (2)). As a result of this correction, the pre-emission photometric value Y is under-corrected for a subject whose reflectance is higher than the standard reflectance, so that the amount of light emission in the main emission is prevented from being insufficient, and underexposure is prevented.
When the pre-flash photometric value Y is smaller than the target photometric value Yref−2EV, a value obtained by adding 2EV to the pre-flash photometric value Y is set as a corrected photometric value Y ′ (formula (3)). As a result of this correction, the pre-emission photometric value Y is over-corrected for a subject whose reflectance is lower than the standard reflectance.
The constants A and B need not be 2 or equal, and a real number greater than 0 and 4 or less is a practical value.

  In the embodiment of the present invention, when calculating the photometric result on the entire photographing screen, the weighted average of the photometric values is calculated by placing weight on the in-focus distance measuring area, and the photometric result on the entire photographing screen is obtained. The photometry area (image area) classification means 50h of the controller 50 converts the photometry area into three areas of a focus area, a semi-focus area, and a non-focus area from the AF focus information (the absolute value of the detected defocus amount). Sort. The focus area is a distance measurement area in which the absolute value of the defocus amount obtained by the AF operation is within a predetermined threshold 1. The focus area is displayed in the viewfinder or on the live view display screen displayed on the display 23 so that the user can know the focus position, such as outline enhancement of the focus area. The semi-focus area is a distance measurement area in which the absolute value of the defocus amount is larger than the predetermined threshold 1 and within the predetermined threshold 2 (threshold 1 <threshold 2). Not notified. The out-of-focus area refers to a distance measurement area where the absolute value of the defocus amount is larger than the threshold value 2 or the defocus amount cannot be obtained due to factors such as insufficient contrast. In this embodiment, the photometry area and the image area are the same area, but can be separate areas. The photometric area and the image area may be different in size.

In the example of FIG. 3B, the ranging area marked with a circle represents a focused area that is in focus. Further, the distance measurement area marked with Δ is not focused but represents a semi-focus area close to the focused state. The in-focus area and the semi-in-focus area marked with ○ and Δ are treated as including priority subjects or priority subjects. Photometric value correcting means 50f of the controller 50, the pre-emission photometric value at least focus area, the standard reflectance subject is corrected so as to approach the theoretical pre-emission photometric value when there the same distance.

  In the present embodiment, the photometry area corresponding to the focus measurement area (focus area), the photometry area corresponding to the semi-focus distance measurement area (semi-focus area), and the photometry corresponding to the non-focus distance measurement area. The area (non-focus area) is weighted in order of the focus area, the semi-focus area, and the non-focus area. For weighting, for example, the in-focus area is α, the semi-in-focus area is β, and the out-of-focus area is 1. That is, the weighting ratio, in-focus area: semi-in-focus area: non-in-focus area is α: β: 1. However, α and β are positive real numbers, and α ≧ β ≧ 1 and α ≠ 1. The weights α and β can be arbitrarily set in the range of 2 to 5, for example, but α = 4, β = 2, and the ratio of in-focus area: semi-in-focus area: non-in-focus area is 4: 2: 1. It is preferable.

  FIG. 5 is a flowchart showing the flash pre-flash photographing operation of the digital single lens reflex camera 10. The controller 50 comprehensively controls the flash pre-flash photographing operation according to a program written in the flash ROM 51. The controller 50 is activated when the power switch is turned on, and enters the flash pre-flash shooting process in a shooting standby state in which shooting is possible with the flash pre-flash shooting mode selected.

  The controller 50 checks whether or not there is an AF instruction (whether or not the AF / photometry switch 35 is on) (S101) and repeats until there is an AF instruction (S101: NO, S101). If it is determined that there has been an AF instruction (S101: YES), the AF operation is started (S103), and the focus lens group L2 is moved to a focus position where the absolute value of the defocus amount detected by the AF operation is zero. The in-focus state determination unit 50b of the controller 50 moves the focus lens group L2 to the in-focus position, and then performs in-focus determination for each distance measurement area based on the detected defocus amount. The subject distance calculation unit 50c The subject distance of the ranging area determined to be in focus is calculated (S105). The photometry area classification means 50h classifies the distance measurement area determined to be in focus into the focus area, classifies the distance measurement area determined as semi-focus, and classifies the other distance measurement areas into the non-focus area. .

  Thereafter, the controller 50 checks whether or not there has been a shooting instruction (whether or not the release switch 36 has been turned on) (S107), and periodically repeats the check until there is a shooting instruction (S107: NO, S107). When receiving a shooting instruction, the controller 50 performs an AE calculation to determine an exposure value (shutter speed (exposure time) TV, aperture value AV, ISO sensitivity SV) for actual shooting (S107: YES). , S109). Further, the controller 50 determines electronic shutter speed TV (exposure time) for pre-light emission, aperture value AV, ISO sensitivity SV and guide number Gno (guide value GV) for pre-light emission as flash pre-light emission conditions (S111). As the aperture value A, a normally open aperture value is set.

  After determining the pre-flash exposure condition, the controller 50 first detects the steady light metering value without pre-flash by the pre-flash metering means 50d without pre-flashing the built-in flash device 40 (S113). Subsequently, the controller 50 pre-flashes the built-in flash device 40 with the previously determined guide number Gno and pre-flashes with the pre-flash metering means 50d to detect the pre-flash photometric value (S115). The pre-flash photometric means 50d takes the difference between the pre-flash photometric value and the steady-light photometric value as the pre-flash photometric value Y (S117). The order of stationary light metering and pre-flash metering may be reversed.

Target photometric value calculating means 50e of the controller 50 calculates a target photometric value Yref based on the subject distance information focus area where the subject distance calculating unit 50c is calculated photometric value correcting means 50f is pre-emission photometric value Y Then, the corrected photometric value Y ′ is calculated (S119). The weighting means 50i of the controller 50 weights the post-correction photometric value Y ′ of the focus area and the photometry values of the semi-focus area and the non-focus area based on the focus information determined by the focus state determination means 50b ( S121). The controller 50 (exposure value calculation means) calculates the photometric value (luminance BV) of the entire screen based on the above-mentioned weighted photometric value (S123). Further, the main light emission amount calculating means 50g of the controller 50 calculates the main light emission amount (main light emission guide number Gno) based on the calculated photometric value of the entire screen and the exposure value for photographing (S125). The photometric value is a weighted average value of the corrected photometric value Y ′, and the exposure value for photographing is the actual photographing exposure value set in step S109.

  The controller 50 performs the main photographing operation by causing the built-in flash device 40 to emit the main light according to the calculated main light emission amount, and records the photographed image signal in the flash memory 53 and displays it on the display 23 (S127). The shooting operation is terminated (END).

  In the shooting scene shown in FIG. 6, a person and a part of a tree are located at the same distance from the camera as subjects in the shooting screen 61, and both the person and a part of the tree are in focus. is there. In this case, the camera (in-focus state determination unit 50b) detects the face of the person and determines the subject whose face is detected as the priority subject. In this embodiment, the focus area and the semi-focus area including the face as the priority subject, and the continuous area and the focus area including the body of the person who is the priority subject are semi-focus. The focal area is set as the priority subject area. The above-mentioned focus area of the priority subject is marked with a circle, and the semi-focus area is marked with a triangle. The above-mentioned pre-flash metering values are corrected and weighted for the focus area and quasi-focus area of the priority subject, and other out-of-focus areas for the focus area and quasi-focus area that were not determined as the priority subject. Treat as well.

  The shooting scene shown in FIG. 7 is a state in which two persons are standing at the same distance from the camera as main subjects in the shooting screen 61 and are focused on both of the two persons. At this time, the camera detects the faces of two persons. In this case, the camera (in-focus state determination unit 50b) determines the person having the larger face area as the priority subject. In FIG. 7, the person on the left side is the priority subject. In the present embodiment, a focus area and a semi-focus area including the face of a person with a larger face (priority subject), and a region continuous with these areas, including the body of the person who is the priority subject. The in-focus area and the semi-in-focus area are designated as priority subject areas. The above-mentioned focus area of the priority subject is marked with a circle, and the semi-focus area is marked with a triangle. The pre-flash metering values are corrected and weighted for the in-focus area and semi-in-focus area that contain the person determined to be the priority subject, and the in-focus area and semi-in-focus area of the person who has not been determined to be the priority object. The focus area is handled in the same manner as other non-focus areas.

  The shooting scene shown in FIG. 8 is a state in which three flowers are standing at the same distance from the camera as main subjects in the shooting screen 61 and are in focus on all three flowers. In this case, the camera (focus state determination means 50b) determines the subject closest to the center of the shooting screen as the priority subject. In the embodiment of FIG. 8, the center flower of the three flowers is determined as the priority subject, and the focus area and the semi-focus area including the center flower as the priority subject are set as the priority subject areas. The above-mentioned focus area of the priority subject is marked with a circle, and the semi-focus area is marked with a triangle. The above-mentioned pre-flash metering values are corrected and weighted for the in-focus area and the semi-in-focus area that contain flowers that have been determined to be priority subjects, and the in-focus areas of other flowers that were not determined to be priority subjects. The focus area is handled in the same manner as other non-focus areas.

  The embodiment in which the present invention is applied to a digital single-lens reflex camera equipped with a pupil division phase difference type automatic focusing device has been described above. However, the present invention describes a so-called mirror equipped with a so-called image contrast type automatic focusing device. This can be applied to a digital SLR camera or a compact digital camera. In the case of the image contrast method, the in-focus state is detected from image signals in a plurality of distance measuring areas captured by the image sensor 31 while moving the focusing lens group L2 in the optical axis direction, and the in-focus state is detected. When this is done, the focusing lens unit L2 is moved to the position in the optical axis direction where the in-focus state is achieved. In the case of the image contrast method, since the contrast of the photographed image is used, the focusing accuracy is high, it is easy to match the distance measurement area and the photometry area, and the area coincidence between the distance measurement area and the photometry area is high. The distance measurement area and the light measurement area are associated with each other, and the evaluation value is corrected according to the focus information and the distance information only for the light measurement area that substantially matches the distance measurement area, and the evaluation value is set for the light measurement area that does not match the distance measurement area. It is practical to set so that no correction is made.

  The pre-flash control and the main flash control may be performed by either the built-in flash device 40 or the external flash device 41 or both.

10 Digital SLR camera (photographing device)
DESCRIPTION OF SYMBOLS 11 Camera body 12 Main mirror 15 Viewfinder optical system 18 Distance sensor 20 Shutter device 21 AF motor 22 Aperture motor 24 AF drive circuit 25 Aperture drive circuit 26 Shutter drive circuit 31 Image sensor 32 Image sensor drive / signal processing circuit 33 Brightness sensor 34 Luminance sensor drive / signal processing circuit 40 Built-in flash device (flash device)
41 External flash device (flash device)
50 controller 50a focus adjusting means 50b focusing state determining means 50c subject distance calculating means 50d pre-emission photometric means (photometric means)
50e target photometric value calculating means 50f photometric value correcting means 50g main light emission amount setting means 50h photometric area sorting means 50i weighting means 51 ROM (EEPROM)
52 SDRAM
53 Flash memory 61 Shooting screen 101 Shooting lens 103 Aperture device 105 Distance detection means

Claims (6)

A flash device,
Focus adjusting means for focusing on a subject in one of a plurality of ranging areas;
In-focus state determining means for determining an in-focus state for subjects in the plurality of ranging areas;
Subject distance calculating means for calculating the distance of the subject in the distance measurement area focused by the focus adjusting means;
Prior to the actual shooting, pre-flash metering values based on pre-flash only are detected from a plurality of metering areas from pre-flash metering values when the flash device is pre-flashed and stationary light metering values when pre-flash is not fired. Luminescence photometric means,
Target metering value calculating means for calculating a target metering value obtained by pre-flashing the flash device when the subject at the distance calculated by the subject distance calculating means is a standard subject;
The pre-flash photometric value of the pre-flash photometric means in the photometry area corresponding to the focus detection area determined by the focus state determining means as the focused state is corrected based on the target photometric value of the target photometric value calculating means. A photometric value correction means for obtaining a corrected photometric value,
A main light emission amount setting means for setting the main light emission amount by the flash device based on the corrected photometric value corrected by the photometric value correction means ,
The pre-flash photometric value of the photometry area corresponding to the focus detection area determined to be in focus by the in-focus state determining means is Y, the target photometric value is Yref, and the photometric value corrected by the photometric value correcting means is Y ′. In this case, the photometric value correction means calculates the corrected photometric value Y ′ by the following equations (1), (2), (3) .
Y '= Yref ... (1)
(However, Yref−A ≦ Y ≦ Yref + B)
Y ′ = Y−B (2)
(However, Yref + B <Y)
Y '= Y + A (3)
(However, Y <Yref-A)
However, the pre-flash photometric value Y, the target photometric value Yref, and the corrected photometric value Y ′ are apex display brightness values, and the constants A and B are positive apex display exposure values EV. The photographing apparatus according to claim 1 , wherein the photometric area is classified into one of a focused area, a semi-focused area, and a non-focused area according to the focused state determined by the focused state determining unit. And a metering value correction unit weights each of the in-focus area, the semi-in-focus area, and the out-of-focus area in the order of the in-focus area, the semi-in-focus area, and the out-of-focus area. A photographing device that calculates post-correction photometric values for all photometric areas. The photographing apparatus according to claim 1 or 2, wherein the photographing optical system includes a focusing lens group that moves in the optical axis direction to adjust the focus, and a lens position detection unit that detects a position of the focusing lens group in the optical axis direction. And the focus adjusting means detects the phase difference between a pair of subject images by dividing the subject luminous flux that has passed through the photographing optical system into different distance measurement areas, and based on the detected phase difference. A focus position of the focus lens group is detected, the focus lens group is moved to the detected focus position, and the subject distance calculation unit is configured to detect the focus adjustment unit from the lens position detected by the lens position detection unit. Calculates the distance of the subject within the distance measurement area focused by the focus state determination means, and calculates the defocus amount from the phase difference between the pair of subject images for each distance measurement area. In Determining imaging device focus state Zui. The imaging apparatus according to claim 3 , further comprising a luminance sensor that receives a subject light flux that has passed through the imaging optical system and measures the light for each of a plurality of photometric areas, and the distance measuring area overlaps with the photometric area. . The imaging apparatus according to claim 1 or 2 , wherein an imaging optical system including a focusing lens group that moves in an optical axis direction to adjust a focus, and an optical image formed by the imaging optical system at the time of actual imaging are electrically An image sensor that converts the image signal into memory, a memory unit that records the image signal, and a brightness sensor that detects the brightness of an optical image formed by the photographing optical system separately from the image sensor, The pre-flash photometric means is a photographing device for detecting the pre-flash photometric value and the steady-light photometric value based on the luminance signal imaged by the luminance sensor. The imaging apparatus according to claim 5 , wherein the focus adjusting unit detects a focused state based on image signals in a plurality of ranging areas captured by the imaging element while moving the focusing lens group in an optical axis direction. When the focus state is detected, the photographing apparatus moves the focus lens group to the optical axis direction position where the focus state is obtained.

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