JP2015219416A - Imaging apparatus and exposure amount control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of performing photographing with suitable exposure in flash photography, regardless of whether or not a scene is a backlight scene.SOLUTION: The imaging apparatus includes a photographic optical system, irradiation means for irradiating a subject with illumination light, photometric means for dividing a photographing area into a plurality of division areas, to perform photometry, and exposure amount control means for controlling an exposure amount during photographing on the basis of the photometric result of the photometric means. The exposure amount control means acquires first photometric information obtained by the photometric means, when the illumination light is irradiated by the irradiation means prior to photographing and second photometric information obtained by the photometric means, when the illumination light is not irradiated by the irradiation means, calculates at least a photometric value on a first area and a photometric value on a second area on the basis of the first photometric information and the second photometric information, and controls the exposure amount during photographing on the basis of at least two kinds of photometric values.

Description

  The present invention relates to an imaging apparatus and an exposure amount control method.

  When it is desired to shoot both the main subject and the background with appropriate exposure even in a backlight scene, the main subject is irradiated by flash emission. For example, in Patent Document 1 below, an imaging apparatus determines a backlight scene, and performs exposure adjustment in accordance with a bright output of an output by photometry at the center of the shooting screen and an output by photometry of the entire shooting screen. Therefore, strobe light emission control that prevents saturation of the output of the imaging means is described.

JP 2004004361 A

  By the way, in flashing scenes, if flash emission is performed with the exposure of the imaging device set to the main subject, both the main subject and the background will be overexposed. Therefore, it is preferable to determine exposure with an emphasis on the background in the backlighting scene. However, if it is controlled to always adjust the exposure to the background during flash photography, the main subject is overexposed in a scene where the main subject is brighter than the background.

  The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide an image pickup apparatus and an exposure amount control method that can take an image with a suitable exposure at the time of flash shooting regardless of whether it is a backlight scene or not.

  In order to solve the above-described problem, an aspect of the present invention provides an imaging apparatus, an imaging optical system, an irradiation unit that irradiates a subject with illumination light, and an imaging area divided into a plurality of divided areas. Metering means for performing photometry, and exposure amount control means for controlling the exposure amount at the time of photographing based on the photometry result of the photometry means. The exposure amount control means includes first light measurement information obtained by the photometry means when the illumination light is irradiated by the irradiation means prior to photographing, and first light obtained by the photometry means when there is no illumination light irradiation by the irradiation means. Two photometric information are obtained, and at least a photometric value relating to the first region and a photometric value relating to the second region are calculated based on the first photometric information and the second photometric information. The exposure amount at the time of photographing is controlled based on the photometric value.

  According to the above configuration, photometric values relating to at least the first area and the second area in the imaging area can be obtained. These two types of areas are, for example, a background area and a main subject area. By determining the exposure amount based on the photometric values of these two or more areas, it is possible to perform shooting with a suitable exposure during flash shooting regardless of whether it is a backlight scene or not. The first photometric information includes the influence of the illumination light, while the second photometric information does not include the influence of the illumination light, so that a weighted average is taken regardless of the area. It is possible to obtain two photometric values by this method.

  The exposure amount control means may be configured to compare the photometric values of the at least two types of areas and control the exposure amount at the time of photographing based on the brighter photometric value.

  The exposure amount control means obtains a change amount of the photometric information for each divided region based on the first photometric information and the second photometric information, and based on the obtained change amount, a photometric value relating to the first region You may calculate the photometric value regarding a 2nd area | region. In this case, for example, the first region corresponds to a region where the amount of change is smaller than that of the second region, and the second region corresponds to a region where the amount of change is larger than that of the first region. Note that obtaining the amount of change in the photometric information due to illumination light irradiation corresponds to obtaining a contribution rate representing the degree to which illumination light illumination contributes to each subject in the shooting scene.

  The exposure amount control means calculates at least two types of weighting information respectively corresponding to at least two types of regions based on the amount of change, and calculates photometric values of at least two types of regions based on the at least two types of weighting information. It may be calculated.

  The at least two types of weighting information include the first weighting information in which the weighting of the first region is larger than that of the second region, and the second weighting of the second region is larger than that of the first region. Weighting information may be included.

  When calculating the first weighting information, the exposure amount control means sets the weighting of the first area to be larger than that of the second area, and the amount of change among the plurality of divided areas is a predetermined change. For areas larger than the amount, a uniform weighting value may be set so that the influence is suppressed. Further, when calculating the second weighting information, the exposure amount control means sets the weighting of the second region to be larger than that of the first region, and the change amount among the plurality of divided regions is predetermined. A uniform weighting value may be set for an area smaller than the change amount so that the influence can be suppressed.

  Note that the predetermined change amount is, for example, a change amount of photometric information in an area regarded as a main subject (that is, a contribution rate of illumination light irradiation in an area regarded as a main subject).

  The exposure amount control means may set an upper limit value and / or a lower limit value of the weight value when calculating at least two types of weight information based on the change amount.

  The exposure amount control means corrects the exposure amount at the time of photographing based on at least one of the reduction characteristics of the peripheral light amount caused by the characteristics of the photographing optical system, the light distribution characteristics of the irradiation means, and the reflection characteristics of the irradiation light quantity. good.

  Further, another aspect of the present invention provides an exposure amount control method executed for controlling an exposure amount in an imaging apparatus, where illumination light is irradiated by an irradiation unit prior to photographing. First photometric information obtained by the photometric means and second photometric information obtained by the photometric means when no illumination light is irradiated by the illuminating means are obtained, and the first photometric information and the second photometric information are obtained. The photometric value relating to at least the first area and the photometric value relating to the second area are calculated based on the above, the photometric values of the at least two kinds of areas are compared, and the exposure amount at the time of photographing is determined based on the brighter photometric value. Control.

  According to the above configuration, photometric values relating to at least the first area and the second area in the imaging area can be obtained. These two types of areas are, for example, a background area and a main subject area. By determining the exposure amount based on the photometric values relating to these two or more areas, it is possible to perform shooting with a suitable exposure during flash shooting regardless of whether it is a backlight scene or not.

  As described above, according to the present invention, it is possible to perform shooting with a suitable exposure during flash shooting regardless of whether it is a backlight scene or not.

It is a block diagram which shows the structure of the imaging device of embodiment of this invention. It is a data flow figure which shows an example of the photometry value determination algorithm by embodiment of this invention. It is a data flow figure which shows the other example of the photometric value determination algorithm by embodiment of this invention. It is a figure explaining the production | generation of the weight map in the photometric value determination algorithm shown in FIG. It is a figure explaining the production | generation of the weight map in the photometric value determination algorithm shown in FIG. It is a flowchart which shows the exposure control by embodiment of this invention.

  Hereinafter, an imaging apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the imaging device as an embodiment of the present invention will be described as a digital single-lens reflex camera. However, the imaging device is not limited to a digital single-lens reflex camera, for example, a mirrorless single-lens camera, a compact digital camera, A camcorder, a tablet terminal, a PHS (Personal Handy phone System), a smartphone, a feature phone, or a portable game machine may be replaced with another type of device having a shooting function.

[Configuration of the photographing apparatus 1]
FIG. 1 is a block diagram showing a configuration of the photographing apparatus 1 of the present embodiment. As shown in FIG. 1, the photographing apparatus 1 includes a photographing lens system 10 (photographing lenses 11 and 12). A diaphragm 13 is disposed between the photographing lens 11 and the photographing lens 12. A mirror 14 is disposed behind the taking lens system 10. The mirror 14 is a half mirror, and is disposed in a posture in which the half mirror surface is about 45 ° with respect to the optical axis AX of the photographing lens system 10.

  A luminous flux from the subject (subject luminous flux) passes through the taking lens system 10 and enters the mirror 14. Behind the mirror 14, a focal plane shutter 15 and an image sensor 16 are arranged in this order from the mirror 14 side. Above the mirror 14, a diffusion plate (focus plate or focus plate) 18 and a pentaprism 17 are arranged in this order from the mirror 14 side.

  Part of the subject luminous flux incident on the mirror 14 is reflected by the mirror 14 and incident on the pentaprism 17 via the diffusion plate 18. The diffusion plate 18 is disposed at a position equivalent to the imaging surface of the imaging element 16. Therefore, the subject light flux that has passed through the photographic lens system 10 forms an image on the diffusion plate 18. The pentaprism 17 has a plurality of reflection surfaces, and forms an erect image by reflecting an object image formed and incident on the diffusion plate 18 by each reflection surface, and emits the image toward the eyepiece lens 19. The eyepiece 19 re-images the subject image formed on the diffusion plate 18 and erected by the pentaprism 17 into a virtual image suitable for the photographer's observation. Thereby, the photographer can observe the subject image by looking into the eyepiece lens 19.

  The operation member 32 includes various switches necessary for the user to operate the photographing apparatus 1, such as a power switch, a release switch, a photographing mode switch, and a zoom switch. When the user presses the power switch, power is supplied from the battery (not shown) to the various circuits of the photographing apparatus 1 through the power line. After supplying power, a CPU (Central Processing Unit) 31 accesses a predetermined memory area (not shown), reads out a control program, loads it into the work area, and executes the loaded control program, whereby the entire photographing apparatus 1 is executed. Control.

  The CPU 31 drives and controls the aperture 13 via the aperture drive circuit 22 so that an appropriate exposure is obtained based on a photometric value measured by a photometric sensor 26 such as a TTL (Through The Lens) exposure meter. The state display device 33 (for example, LCD (Liquid Crystal Display)) displays the shooting mode, the appropriate exposure time at that time, the F value, and the like.

  When the release switch is pressed halfway, the CPU 31 determines the position and positional relationship between the photographing lens 11 and the photographing lens 12 on the optical axis AX via the lens control circuit 21 based on the detection result of the AF (Autofocus) sensor 25. Control. Thereby, the focus state of the photographic lens system 10 is adjusted. Next, when the release switch is fully pressed, the CPU 31 controls the drive of the focal plane shutter 15 via the shutter drive circuit 24 and causes the mirror 14 to return quickly. That is, the CPU 31 raises the mirror 14 via the mirror driving circuit 23 only during the period immediately before the front film travel of the focal plane shutter 15 is started and immediately after the rear curtain travel, so that the optical axis AX of the photographing lens system 10 is The mirror 14 is retracted from the parallel optical path.

  The subject luminous flux that has passed through the photographic lens system 10 is imaged on the imaging surface of the imaging element 16 while the focal plane shutter 15 is open. The imaging element 16 is, for example, a CCD image sensor or a CMOS image sensor, and accumulates an optical image formed by each pixel on the imaging surface as a charge corresponding to the amount of light. The image sensor 16 converts the accumulated charge into a voltage (herein referred to as “pixel signal”) by a floating diffusion amplifier, and outputs the converted pixel signal to the A / D conversion circuit 27. The A / D conversion circuit 27 performs A / D conversion on the input pixel signal and outputs it to a DSP (Digital Signal Processor) 41.

  The DSP 41 controls the charge accumulation operation and the pixel signal readout operation of the image sensor 16 and performs predetermined signal processing on the pixel signal input from the A / D conversion circuit 27. Specifically, the DSP 41 performs predetermined signal processing such as color interpolation, matrix calculation, and Y / C separation on the pixel signal input from the A / D conversion circuit 27 to perform luminance signal Y, color difference signal Cb, Cr is generated and compressed in a predetermined format such as JPEG (Joint Photographic Experts Group). For example, the buffer memory 42 is used as a temporary storage location for processing data when the DSP 41 executes processing.

  A memory card 50 is detachably loaded in the card slot of the card interface 43. The DSP 41 can communicate with the memory card 50 via the card interface 43. The DSP 41 stores the generated compressed image signal (photographed image data) in the memory card 50 (or a built-in memory (not shown) provided in the photographing apparatus 1).

  Further, the DSP 41 performs predetermined signal processing on the signal after Y / C separation, and buffers it in a frame memory (not shown) in units of frames. The DSP 41 sweeps the buffered signal from each frame memory at a predetermined timing, converts it into a video signal of a predetermined format, and outputs it to the LCD control circuit 45 via the monitor interface 44. The LCD control circuit 45 modulates the liquid crystal based on the captured image data input from the DSP 41 and controls the backlight 47 to emit light. Thereby, the photographed image of the subject is displayed on the display screen of the LCD 46. The user can view a real-time through image with a proper brightness photographed with a proper focus through the display screen of the LCD 46.

  For example, when the imaging apparatus 1 is in the flash mode due to a user operation or when the imaging apparatus 1 is detected to be in a dark place, the CPU 31 controls the flash drive circuit 57 to apply a drive voltage to the flash 58. Apply. The flash 58 emits irradiation light (flash) according to the drive voltage to irradiate the subject.

  Next, a photometric value determination algorithm during flash photography according to the present embodiment will be described. As will be described in detail below, the photometric value determination algorithm of the present embodiment determines the final photometric value used for photographing based on the divided photometric data obtained by the photometric sensor 26 and the pre-emission contribution rate. It is processing to do. Note that the pre-flash contribution ratio is information indicating the degree to which the photometric value of the subject has changed between pre-flash (when the flash is emitted with a predetermined light amount before shooting) and before pre-flash. It is. The imaging apparatus 1 of the present embodiment includes a photometric value determination algorithm 1 that performs basic photometric processing based on the divided photometric data and the pre-emission contribution ratio as a photometric value determination algorithm; And a photometric value determination algorithm 2 that further considers (described later).

[Photometric value determination algorithm 1]
First, the photometric value determination algorithm 1 will be described with reference to FIG. FIG. 2 is a data flow diagram showing the flow until the final photometry value is calculated using the divided photometry data and the pre-light emission contribution rate. In FIG. 2 (and FIG. 3), as an example, the division photometry is performed in 45 × 30 divisions. In FIG. 2 (and FIG. 3), the block described as “45 × 30” represents 45 × 30 array data corresponding to the divided area, and the block described as “value” represents one piece of numerical data. (Photometric value).

  The divided photometric data D6 obtained by the photometric sensor 26 is corrected by a predetermined correction algorithm and obtained as corrected divided photometric data D7. The predetermined correction algorithm is, for example, at least one of a peripheral light amount reduction characteristic due to the characteristics of the photographing optical system 10, a light distribution characteristic of the flash 58, and a reflection characteristic of the irradiation light quantity (correction for each color in consideration of reflectance, etc.). Contains. The pre-emission contribution ratio D3 is calculated by comparing the divided photometry data D1 before the pre-emission and the divided photometry data D2 when the pre-emission is performed. That is, the pre-light emission contribution ratio D3 indicates the degree to which the photometric data has changed due to the pre-light emission for each divided region.

  Next, based on the pre-light emission contribution ratio D3, a weight map (1) (reference D4) emphasizing background and a weight map (2) (reference D5) emphasizing the main subject are calculated. Here, the background-oriented weight map (1) calculates the map by increasing the weight as the pre-light emission contribution ratio is lower. On the other hand, the weight map (2) emphasizing the main subject calculates the map by increasing the weight as the pre-light emission contribution ratio is higher. Each weight map will be described with reference to FIG.

The background weight map (1)
・ The lower the pre-flash contribution rate, the greater the weight,
-The higher the pre-light emission contribution rate, the smaller the weight,
Is calculated as follows. In this calculation, a lookup table may be used, or an operation based on a certain conversion law may be used. Further, the upper limit and lower limit of the weight may be limited to a certain value. The above calculation rule is based on the assumption that the higher the pre-light emission contribution ratio is, the closer the distance is (main subject), and the lower the pre-light emission contribution ratio is, the far distance (background) is. It can be said that it is set to be higher.

  Assume that the shooting scene is a backlight scene in which furniture 102, a person 103, and a bowl 104 are arranged from the background 101 toward the front side as shown in FIG. Data of reference numeral 111 in FIG. 4B is array data of pre-light emission contribution ratios of the scene of FIG. 4A (hereinafter referred to as pre-light emission contribution ratios 111). In the pre-light emission contribution rate 111, the value of the pre-light emission contribution rate increases as the object in the foreground (that is, the object in the near side becomes whiter), and the value of the pre-light emission contribution rate increases in descending order from the bowl 104, the human 103, and the furniture. 102, background 101.

  The data indicated by reference numeral 112 in FIG. 4B represents a weight map (1) that emphasizes background. As described above, in the weight map (1) emphasizing background, the weight is increased as the pre-light emission contribution ratio is lower. Therefore, as shown in FIG. 4B, the background-oriented weight map (1) increases in value as the pre-light emission contribution rate decreases (and thus becomes white). That is, in the weight map (1) emphasizing the background, the background 101, the furniture 102, the human 103, and the bowl 104 are arranged in descending order.

On the other hand, in the weight map (2) emphasizing the main subject, the weight is increased as the pre-light emission contribution ratio is higher. Specifically, the weight map (2) emphasizing the main subject is
・ The lower the pre-flash contribution rate, the smaller the weight,
-The higher the pre-flash contribution rate, the greater the weight.
Is calculated as follows. The intent of this calculation is to set the weight to be higher for the part that seems to be the main subject, contrary to the weight map (1) that emphasizes the background. If there is another subject closer than the main subject, the weight of the subject may be too large. In addition, if there are many areas with extremely small weights, such as zero, there is a possibility that the weights are biased to only a small part of the screen, resulting in extreme results. Therefore, it is preferable to set an appropriate upper limit value and lower limit value for the weight.

  The data indicated by reference numeral 114 in FIG. 4C represents a weight map (2) that emphasizes the main subject. As shown in FIG. 4C, the value of the weight map (2) emphasizing the main subject increases as the pre-light emission contribution ratio increases (and thus becomes white). That is, in the weight map (2) emphasizing the main subject, the bowl 104, the human 103, the furniture 102, and the background 101 are arranged in descending order.

  Returning to FIG. 2, the background-oriented photometric value D8 is obtained by taking a weighted average of the background-oriented weight map (1) (D4) and the divided photometric data D7. Also, by taking a weighted average of the weight map (2) emphasizing the main subject and the divided photometry data D7, a photometry value D9 emphasizing the main subject is obtained. The higher (that is, brighter) of the background-oriented photometric value D8 and the main subject-oriented photometric value D9 is adopted as the final photometric value D10. In accordance with the final photometric value D10, the exposure amount is determined, and the flash is subjected to main light emission control and photographing is performed. Although the final photometric value is determined based on the two types of photometric values D8 and D9 here, the final photometric value may be determined based on three or more types of photometric values. Two specific examples of the photometric value calculation are shown below.

(Example 1)
Assume that in a backlight scene, the luminance of the main subject is Lv5 and the luminance of the background is Lv10. In this case, since the brightness of the background is high, the background-oriented photometric value D8 is a value that places importance on the background, and is, for example, Lv9.5. On the other hand, the metering value D9 with emphasis on the main subject is a metering value with emphasis on the main subject, and is, for example, Lv5.5. Of the two photometric values, the brighter is Lv9.5, so Lv9.5 is adopted as the final photometric value.

  When flash photography is performed with this exposure, the background is photographed by 0.5 Ev over the proper exposure, and the main subject is properly exposed by the flash. As a result, it is possible to obtain an image in which the main subject and the background are exposed in a well-balanced manner while leaving the backlighting.

(Example 2)
Contrary to Example 1 above, a scene is assumed in which only the main subject is illuminated in a dark background. Assume that the luminance of the main subject is Lv10 and the luminance of the background is Lv5. In this case, the background-oriented photometric value D8 is a value that places importance on the background, and is, for example, Lv5.5. On the other hand, the metering value D9 with emphasis on the main subject is a metering value with emphasis on the main subject, and is, for example, Lv9.5. Of the two photometric values, the brighter is Lv9.5, so Lv9.5 is adopted as the final photometric value.

  When flash photography is performed with this exposure, the main subject is photographed over 0.5 Ev, and the background is photographed 4.5 Ev under. Although the main subject is flashed, the main subject is sufficiently bright, so that the amount of light emission can be suppressed considerably. As a result, the background is almost completely dark, but it is avoided that the main subject is greatly blown out.

[Photometric value determination algorithm 2]
Next, a photometric value determination algorithm 2 that further considers the target value of the main light emission will be described with reference to FIG. In FIG. 3, elements equivalent to those in FIG.

  The divided photometric data D6 obtained by the photometric sensor 26 is corrected by a predetermined correction algorithm and obtained as corrected divided photometric data D7. The pre-emission contribution ratio D3 is calculated by comparing the divided photometry data D1 before the pre-emission and the divided photometry data D2 when the pre-emission is performed.

  In the photometric value determination algorithm 2, the pre-emission contribution rate is analyzed to determine how many portions of the contribution rate are to be properly exposed, thereby determining the main emission light quantity. At this time, the contribution rate that achieves proper exposure when the main light is emitted is referred to as a “target value of the main light emission”. As an example, in the scene as shown in FIG. 4A, a value close to the contribution rate of the main subject, the human, is the target value of the main light emission.

  The target value of the main light emission (reference numeral D21) is used for calculation of the weight map (1) (reference numeral D24) emphasizing the background and the weight map (2) (reference numeral D25) emphasizing the main subject. An example of calculating each weight map will be described with reference to FIG. Here again, it is assumed that the shooting scene is the backlight scene shown in FIG. FIG. 5A is a diagram for explaining generation of a weight map (1) emphasizing background, and FIG. 5B is a diagram for explaining generation of a weight map (2) emphasizing main subject.

The background-oriented weight map (1) is a map in which the weight is increased as the pre-light emission contribution ratio is lower. The background weight map (1) is generated according to the following rules as an example based on the pre-emission contribution ratio data.
(a1) Areas whose contribution rate is lower than the target value of main light emission are weighted according to the difference from the target value.
(a2) For areas where the contribution rate is equal to or greater than the target value of the main light emission, the weight is set to a preset minimum value.
(a3) The weight is limited to a certain value for both the upper and lower limits.
Here, it is assumed that the target value of the main light emission is determined to be a value close to the contribution rate of the human being who is the main subject. At least by applying the above rules (a1) and (a2), the background area that is not brightened by the main flash without using the photometric value of the main subject area that becomes brighter than appropriate by the main flash is used as much as possible. Accordingly, it becomes possible to perform photometry with emphasis.

  In the case of this target value, as indicated by the pre-emission contribution rate 111 in FIG. 5A, the area of the background 101 and the furniture 102 is an area below the target value, and the area of the human 102 and the pot 103 is equal to or greater than the target value. It is considered as an area. Therefore, the weight map (1) emphasizing the background is a map as indicated by reference numeral 115 in FIG. More specifically, in the background-oriented weight map (1), the area where the contribution rate is recognized to be equal to or higher than the target value (the area of the bowl 104 and the human 103) is a preset minimum value (that is, black), The area where the contribution rate is lower than the target value (the furniture 102 and the background 101 area) is set to a value corresponding to the difference between the contribution rate and the target value.

Next, the main subject weight map (2) will be described. The weight map (2) emphasizing the main subject is a map in which the weight is increased as the pre-light emission contribution ratio is higher. The weight map (2) emphasizing the main subject is generated according to the following rules, for example, based on the pre-emission contribution rate data.
(b1) Areas where the contribution rate is equal to or greater than the target value of main light emission are weighted according to the difference from the target value.
(b2) For areas where the contribution rate is lower than the target value of the main light emission, the weight is set to a preset minimum value.
(b3) The weight is limited to a certain value for both the upper and lower limits.
By applying at least the rules (b1) and (b2) above, it is possible to emphasize the main subject area that is brighter than appropriate with the main flash as much as possible, but not to use the photometric values of the background area that is not bright with the main flash as much as possible. It becomes possible.

  A map 116 in FIG. 5B is a weight map (2) emphasizing the main subject generated according to the rules (b1) to (b3). As shown in FIG. 5B, the area where the pre-light emission contribution ratio is lower than the target value (the area of the background 101 and the furniture 102) has a preset minimum value (that is, black), and the pre-light emission contribution ratio is The area that is equal to or greater than the target value (the area of the human 102 and the bowl 103) is set to a value corresponding to the difference between the pre-light emission contribution rate and the target value.

  Returning to FIG. 3, the background-oriented photometric value D28 is obtained by taking a weighted average of the corrected divided photometric data D7 using the background-oriented weight map (1) (symbol D24). Further, the corrected subject photometric data D7 is obtained by taking a weighted average using the weight map (2) (reference D25) with emphasis on the main subject to obtain the photometry value D29 with emphasis on the main subject. The higher (that is, brighter) of the background-oriented photometric value D28 and the main subject-oriented photometric value D29 is adopted as the final photometric value D30. In accordance with the final photometric value D30, the exposure amount is determined, and the flash is controlled to perform the main light emission to perform photographing.

  FIG. 6 is a flowchart showing an exposure control process having the photometric value determination algorithm described with reference to FIGS. 2 and 3 as its main content. The exposure control process is stored as a program in a ROM (not shown) connected to the CPU 31, is activated by a predetermined user operation such as half-pressing the release button, and is executed under the control of the CPU 31. When the exposure control process is activated, pre-emission is performed and the pre-emission contribution rate described above is calculated (step S1).

  Next, a weight map (1) emphasizing background and a weight map (2) emphasizing main subject are generated based on the pre-light emission contribution ratio (step S2). When the photometric value determination algorithm 2 is executed, in step S2, the target value of the main light emission is further added as described above. Next, the weighted average of the corrected divided photometric data is calculated according to the background weighted map (1) to calculate the background weighted photometric value, and the corrected divided metered data is used as the main subject weighted map (2). Thus, the photometric value with emphasis on the main subject is calculated by performing a weighted average according to (Step S3).

  Of the photometry values emphasizing the background and the photometry values emphasizing the main subject, the brighter one is adopted as the final photometry value (step S4). In accordance with the final photometric value, the exposure amount is determined, and the flash is subjected to main light emission control to perform photographing (step S5).

  As described above, according to the present embodiment, it is possible to perform shooting with a suitable exposure during flash shooting regardless of whether it is a backlight scene or not. By calculating the weight map (1) emphasizing the background and the weight map (2) emphasizing the main subject as described above, the subject in the shooting scene can be accurately distinguished, and thus the above-described effect is exhibited. In particular, when the photometric value determination algorithm 2 is used, the subject in the photographic scene can be more accurately distinguished, and thus the above-described effect is further exhibited.

  The above is the description of the exemplary embodiments of the present invention. Embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical idea of the present invention. For example, the embodiment of the present invention also includes contents appropriately combined with embodiments or the like clearly shown in the specification or obvious embodiments.

DESCRIPTION OF SYMBOLS 1 Shooting device 10 Shooting lens system 11, 12 Shooting lens 13 Diaphragm 14 Mirror 15 Focal plane shutter 16 Imaging element 17 Penta prism 18 Diffusion plate 19 Eyepiece 21 Lens control circuit 22 Diaphragm drive circuit 23 Mirror drive circuit 24 Shutter drive circuit 25 AF Sensor 26 Photometric sensor 27 A / D conversion circuit 28 Temperature sensor 31 CPU
32 Operation member 33 Status display device 41 DSP
42 Buffer memory 43 Card interface 44 Monitor interface 45 LCD control circuit 46 LCD
47 Backlight 50 Memory card 57 Flash drive circuit 58 Flash

Claims (9)

Photographic optics,
An irradiation means for irradiating the subject with illumination light;
A photometric means for measuring light by dividing the shooting area into a plurality of divided areas;
Exposure amount control means for controlling the exposure amount at the time of photographing based on the photometry result of the photometry means,
The exposure amount control means includes
The first photometric information obtained by the photometric means when illumination light is emitted by the illuminating means prior to photographing, and the second photometric means obtained by the photometric means when no illumination light is emitted by the illuminating means. Get photometric information and
Calculating at least a photometric value relating to the first area and a photometric value relating to the second area based on the first photometric information and the second photometric information;
Controlling the exposure amount at the time of photographing based on the photometric values of the at least two types of areas;
An imaging apparatus characterized by the above.   2. The imaging according to claim 1, wherein the exposure amount control unit compares the photometric values of the at least two types of regions and controls the exposure amount at the time of photographing based on a brighter photometric value. apparatus. The exposure amount control means obtains a change amount of photometric information for each divided region based on the first photometric information and the second photometric information, and based on the obtained change amount, the first region A photometric value relating to the second region and a photometric value relating to the second region,
The first region corresponds to a region where the amount of change is small relative to the second region, and the second region corresponds to a region where the amount of change is large relative to the first region. The imaging apparatus according to claim 1, wherein: The exposure amount control means includes
Calculating at least two types of weighting information respectively corresponding to the at least two types of regions based on the change amount;
The imaging apparatus according to claim 3, wherein photometric values of the at least two types of areas are calculated based on the at least two types of weighting information.   The at least two types of weighting information include first weighting information in which the weighting of the first region is greater than that of the second region, and weighting of the second region with respect to the first region. The imaging device according to claim 4, comprising second weighting information that increases. The exposure amount control means includes
When calculating the first weighting information, the weighting of the first region is set to be larger than the second region, and the change amount among the plurality of divided regions is a predetermined change amount. For a larger area, set a uniform weighting value to suppress the effect,
When calculating the second weighting information, the weighting of the second area is set to be larger than the first area, and the change amount of the plurality of divided areas is a predetermined change amount. For smaller areas, set a uniform weighting value to suppress the effect,
The imaging apparatus according to claim 5.   5. The exposure amount control unit sets an upper limit value and / or a lower limit value of a weight value when calculating the at least two types of weight information based on the change amount. The imaging device according to claim 6.   The exposure amount control means corrects the exposure amount at the time of photographing based on at least one of a reduction characteristic of the peripheral light amount caused by the characteristics of the photographing optical system, a light distribution characteristic of the irradiation means, and a reflection characteristic of the irradiation light quantity. The imaging apparatus according to any one of claims 1 to 7, wherein An exposure amount control method executed for controlling an exposure amount in an imaging apparatus,
First photometric information obtained by photometric means when illumination light is irradiated by the illuminating means prior to photographing, and second photometric information obtained by the photometric means when no illumination light is emitted by the illuminating means. And get the
Calculating at least a photometric value relating to the first area and a photometric value relating to the second area based on the first photometric information and the second photometric information;
Comparing the photometric values of the at least two regions and controlling the exposure amount at the time of photographing based on the brighter photometric value;
An exposure control method characterized by the above.