JPH0727153B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention provides a photometric device that includes a focus detection device capable of independently detecting the focus of a plurality of photometric regions and divides the photometric region into a plurality of regions for photometry. Regarding a camera that has.

[Prior Art] Conventionally, a photometric device that divides a photometric area into a plurality of areas, outputs a luminance signal for each area, and uses the plurality of luminance signals to provide a proper exposure to a shooting screen. Have been proposed.

For example, Japanese Utility Model Publication No. 51-9271 proposes a photometric device that uses the arithmetic average value of the maximum value and the minimum value among the outputs from a plurality of photoelectric elements as the photometric value.

Further, in Japanese Examined Patent Publication No. 63-7330, the object scene is divided into a central region and two or more regions, and photometry is performed with a plurality of outer regions arranged so as to surround the central region. The brightness of each area is standardized with a reference value that is set between the maximum and minimum values of the brightness, and the field is classified based on this standardized output, and the photometric value is calculated by the classified output. Proposing a photometric device.

In the above conventional example, there was little consideration on the placement of the main subject in the shooting screen, but it is assumed that the main subject is placed in a camera or the like equipped with an automatic focus detection device, and the placement of the main subject in the shooting screen is greatly considered. Is also proposed.

For example, in Japanese Unexamined Patent Publication No. 61-279829, the center of the screen is set as the position where the main subject is arranged, and the object scene is divided into a plurality of regions including a plurality of concentric regions centered at least on the center of the screen. Proposing a photometric device capable of accurately obtaining the luminance of the main subject by selectively using the luminance signal of the concentric area assuming the size of the main subject based on the information of the photographing magnification. There is. Further, in the publication,
In addition to the brightness of the main subject, the brightness of the background is also calculated, and a change in the photometric value calculation formula that uses these brightness differences is also proposed. If it is small, it is possible to give an appropriate exposure suitable for the shooting situation.

Also, in Japanese Patent Laid-Open No. 62-184319, the center of the screen is set as a position where the main subject is easily arranged, and the field of view is divided into a region in the center of the screen, a region outside thereof, and a region outside thereof. ,
It is divided into at least three areas, and the approximate size of the main subject and the shooting situation are simultaneously determined based on the difference between the brightness signals of the plurality of areas and the brightness signals of adjacent areas, and the proper exposure is obtained. We have proposed a photometric device that gives light. In this publication, since the approximate size of the main subject is determined by using the difference in the luminance signal, it depends on the actual size of the main subject as compared with the one in which the size of the main subject is estimated using the shooting magnification. There is an advantage that it is difficult to do so, and it becomes possible to stably obtain an appropriate exposure.

In the two conventional examples cited here, the reason why the center of the screen is assumed to be the position where the main subject is easily arranged is that the focus detection area of the camera equipped with the automatic focus detection device is generally set in the center of the screen. . On the other hand, recent automatic focus detection devices have been proposed that have a plurality of focus detection areas. In a camera equipped with such an automatic focus detection device, each of the multiple focus detection devices (hence the screen It is easy to arrange the main subject (in a specific area other than the central portion).

Therefore, Japanese Laid-Open Patent Publication No. 1-220720 has been proposed as a photometric device that is suitable for a camera having a plurality of focus detection areas. In this publication, by applying the proposal of Japanese Patent Laid-Open No. 61-279829, which obtains the brightness of the main subject based on the information on the above-described photographing magnification, in addition to the information on the photographing magnification and the focal length of the photographing lens, Based on the information of the selected focus detection area and the focus state of other focus detection areas when the area is in focus, the photometric area and the calculation for changing the weighting for the photometric area, The luminance of the main subject is accurately obtained and is output as a photometric value for natural light photography.

[Problems to be solved by the invention]

Among the photometric devices of the above-mentioned conventional example, the one configured to be a photometric device suitable for a camera equipped with a distance measuring device capable of independently measuring a plurality of points in a field is disclosed in the above-mentioned JP-A-1-202720. Only the official gazette. Although this publication adds the idea of considering the in-focus state of a plurality of focus detection points, the basic technical idea is that the subject field to be considered when calculating the photometric value according to the photographing magnification. The one disclosed in Japanese Patent Application Laid-Open No. 61-279829 is used in which the luminance of the main subject is accurately obtained by changing the area.

Therefore, if the actual size of the main subject is different from the originally assumed size, the luminance of the main subject will be erroneously measured, and it will be difficult to obtain proper exposure. It follows the defect of the device as it is. In addition, according to the technical idea of changing the field area to be considered in the calculation of the photometric value according to the shooting magnification in this manner, when the shooting magnification becomes small, it is necessary to judge the narrow area as the main subject, or There is a discontinuity in the shooting situation judgment as to whether to judge the entire subject in the main field as the main subject. Further, when the difference in luminance between the target area and the other areas is large, there is a problem that the photometric value greatly changes depending on the result of this determination. Further, in such a photometric device, in addition to the luminance signal output from the photometric device, it is indispensable to use the information of the focal length of the photographing lens and the information of the subject distance for the photometric value calculation, and particularly the single lens reflex In the camera, there is also a drawback that a device for communication of various information and signal processing becomes complicated.

Further, in Japanese Patent Laid-Open No. 1-2202720 of the above-mentioned conventional example, in consideration of the focusing states of a plurality of focus detection points, the existence range of the main subject is estimated, and the field area corresponding to each focus detection point is estimated. The idea of changing the weighting for the luminance signal is disclosed. Such an idea is effective when the photographing magnification is large and the main subject occupies a large part of the photographing screen, or when the distance between the plurality of distance measuring points in the photographing screen is small. However, in a general case where a plurality of distance measuring points are arranged at a certain distance in the shooting screen and the proportion of the main subject occupying the shooting screen is not so large, the plurality of focus detection points are in a substantially in-focus state. Since the background is arranged between the distance measuring points, there is a problem that the effect is reduced particularly when the brightness difference between the main subject and the background is large.

[Means for Solving the Problems]

According to the present invention, in a camera including a focus detection unit configured to be capable of independently detecting the focus of a plurality of areas within a shooting screen, a photometric area is divided into a plurality of small areas, and the brightness of each of the divided small areas is detected. And a light receiving means for dividing the plurality of small areas into a preset combination according to the selection of the focus detection area, the first area including the selected focus detection area, and the first area. And a second region surrounding the second region and including the plurality of small regions, and a third region including the plurality of small regions that surrounds the second region and is in a different combination from the second region. Setting means for dividing into at least three areas of the first area and the second area
The brightness of each of the small areas obtained by the light receiving means and the brightness comparing means for comparing the brightness of the second area and the brightness of the third area.
And a calculation unit that calculates a photometric value by using each comparison information obtained by the brightness comparison unit.

In addition, the first, second and third regions divided by the setting means are combinations of the different small regions depending on the selection of the focus detection region and have substantially equal area ratios. It is characterized by being divided.

〔Example〕

1 to 12 are views showing a first embodiment of the present invention, and show a photometric device of a camera having three focus detection areas.

FIG. 1 is a diagram showing a divided shape of a light receiving surface of a light receiving portion for photometry according to the first embodiment of the present invention, showing a state of being projected on a field. In the figure, S ₀₁ , S _02, ..., S ₁₅ represent a plurality of light-receiving small areas divided into 15 areas, and S _L , S _C , and S _R are projected on the field like the photometric light-receiving section. The focus detection field of view is shown. In this embodiment, as shown in FIG.
Three focus detection areas (three focus detection methods include a method of detecting a defocus amount in a previously focused state and a method of detecting an absolute object distance each time). The sub-region and the 12 sub-regions around it are divided into a total of 15 sub-regions, and the brightness of the field is measured for each sub-region.

FIG. 2 is a view showing the optical arrangement of the first embodiment of the present invention,
In the figure, 1 is a projection lens, 2 is a quick return mirror, 3 is a focusing plate, 4 is a penta roof prism, 5 is an image forming lens for photometry, 6 is a light receiving part for photometry, 7 is an eyepiece lens,
8 is a pupil position, 9 is a sub-mirror, 10 is a field mask, 11 is a condenser lens, 12 is a total reflection mirror, 13 is a pupil division mask, 14
Is an image forming lens for focus detection, 15 is a light receiving portion for focus detection, and 16 is a film surface. In the present embodiment, the projection lens 1 forms an image of a subject formed on the focusing plate 3 on the photometric light-receiving section 6 by the photometric imaging lens 5 to produce the 15 small images shown in FIG. A field mask which is divided into regions for photometry and which is arranged near the planned image plane of the projection lens 1.
A part of the subject image formed in the vicinity of 10 is formed on the light receiving portion 15 for focus detection by the image forming lens 14 for focus detection.
Focus detection is performed on a region corresponding to the three focus detection fields shown in the figure.

FIG. 3 is an exploded perspective view of the focus detection optical system shown in FIG. 2. As shown in FIG. 3, the field mask 10 arranged in the vicinity of the projected image plane of the projection lens 1 is provided with three openings. This 3
The subject image formed in the vicinity of one opening is divided into two images by the focus detection imaging lens 14 and focused on the focus detection light receiving unit 15 to detect the focus at three points in the projection screen. Is going.

FIG. 4 is a block diagram showing the circuit configuration of the first embodiment of the present invention. In the figure, SPD ₀₁ , SPD ₀₂ ..., SPD ₁₅ are the 15 light-receiving small areas S ₀₁ , S ₀₂ ..., SPD ₁₅ shown in FIG. 1, respectively.
It is a silicon photodiode (SPD) that measures S ₁₅ , and generates a photocurrent according to the brightness of each small area. AMP ₀₁ , AMP ₀₂ ..., AMP ₁₅ and DI ₀₁ , DI ₀₂ , ..., D
I ₁₅ is an operational amplifier and a compression diode, respectively, and a silicon photodiode (SPD) and an operational amplifier and a compression diode are combined to form a light receiving means corresponding to the 15 light receiving small regions in FIG. . Reference numeral 17 denotes a photometric circuit AECKT, which A / D-converts the output signals corresponding to the luminances of the plurality of light-receiving small areas, and outputs them as digital signals. Reference numeral 18 denotes a metering mode selection switch AESW, which is a so-called evaluation metering in which the camera automatically determines a suitable exposure for the shooting screen in accordance with the brightness distribution state of the field according to the operator's intention and the field of view. It is possible to output a luminance signal of a specific area and, based on this, the operator can select any one of the light metering modes of partial light metering that determines the exposure by utilizing the experience. Reference numeral 15 is a light receiving portion for focus detection corresponding to FIG. 3, and CCD _L1 and CCD _L2 , CCD _C1 and CCD _C2 , and CCD _R1 and CCD _R2 are focus detection fields S _L and _{L of} FIG. 1, respectively.
There are three pairs of light receiving element arrays corresponding to S _C and S _R. In the pair of light receiving element rows, the optical system shown in FIG. 2 and FIG.
Of the field light that forms an image in a predetermined area of the photographic screen, only light fluxes that have passed through two different areas on the exit pupil surface of the photographic lens are extracted and imaged. By comparing the output signals from the pair of light receiving element arrays, the defocus amount can be detected. Reference numeral 19 denotes a focus detection circuit AFCKT, which is based on the output signals from the three pairs of light receiving element arrays provided in the focus detection light receiving unit 15, and as described above, the three focus detection fields S _L , The defocus amount of the object field corresponding to S _C and S _R is detected, and the information of the three defocus amounts is output as a digital signal. Reference numeral 20 denotes a focus detection point selection switch AFSW, which has three focus detection fields S _L , S _C and S _R shown in FIG. 1 depending on the operator's intention.
Whichever of the three focus detection fields of view shown in FIG. 1 and an automatic selection mode in which the camera automatically determines a suitable in-focus position for the shooting screen according to the distribution state of the defocus amount of the object field It is possible for the operator to select one of the arbitrary selection modes for selectively determining one of the focus detection fields of view, and in this arbitrary selection mode, the focus detection point selection switch can indicate the focus detection point to be selected. Is configured. In Fig. 4, the photometric circuit AECKT17,
Metering mode selection switch AES W18, focus detection circuit AFCKT1
9. The focus detection point selection switch AFSW20 input signal is connected to the internal data bus line BUS21 of the microcomputer and used for various controls.

Further, in FIG. 4, reference numeral 22 denotes a central processing unit CP for processing various input signals described above by using programs stored in various memories and instructing the operation of various control mechanisms.
U, 22 are read-only memory ROMs that store various programs, 24 is a random access memory RAM for the work area for calculation, 25 is a display control mechanism DPCNTL, 26 is a shutter speed control mechanism STCNTL, and 27 is a general-purpose input memory. Output port
PIOs, each connected to the internal data bus line BUS21 of the microcomputer. The CPU 22 executes the operation according to the program stored in the ROM 23 by accessing the RAM 24 by using the above-mentioned input signal, performs the display and the shutter time control by the DPCNTL25 and STCNTL26 based on the operation result, and PIO27 The signal for controlling the lens is output to.

Fig. 4 shows the connector CNCT, which communicates between the camera and the lens. 29 is a read-only memory LROM that stores information specific to the taking lens, 30 is the focus position control mechanism AFCNTL of the taking lens, 31 is the aperture control mechanism of the taking lens
This is APCNTL. LROM29 and AFCN installed in the shooting lens
It is connected to the PIO 27 of the camera via TL30, APCNTL31, and CNCT28, and is configured to read out or operate the control mechanism according to the instruction of the CPU of the camera.

In the present embodiment, as described above, the photometric circuit AECKT1
7, metering mode selection switch AESW18, focus detection circuit AFCKT
19. Focus detection point selection switch Based on an input signal from the AFSW 20, a microcomputer is used to control the focus position of the camera display device, the shutter, the photographing lens, and the aperture.

Next, the operation of the first embodiment of the present invention will be described with reference to FIGS.

5 to 8 show a flow chart of the first embodiment of the present invention, FIG. 5 shows a main routine, and FIGS. 6 to 8 show each subroutine.

First, the main routine of FIG. 5 will be described.

STEP01: Main routine In the camera, information corresponding to the brightness of the field, information on the defocus amount of each of a plurality of preset focus detection points, photometric mode selection information based on the will of the photographer,
Also, the focus position control control using the focus detection point selection information and the exposure control and display control by the shutter time and aperture setting are handled. There are other items to be handled by the main routine, such as the drive control of the quick return mirror and the control of the film feeding mechanism, but here, only the items related to the photometric device of the camera of the present invention are taken out. Therefore, others are omitted.

STEP02: Capture the signals of the defocus amount of three focus detection points from AFCKT19. The defocus amount is a pair of line sensors corresponding to each focus detection point, CCD _L1 and CC
It is calculated by detecting the amount of deviation of the output signals of D _L2 , CCD _C1 and CCD _C2 , and CCD _R1 and CCD _R2 , and is captured as a digital signal.

STEP03: Focus detection point selection signal from AFSW20 and AFCKT19
The signal of the amount of differential orcus from
When one of the focus detection points is selected, a signal corresponding to the focus detection point is output, and when the photographer automatically selects the focus detection point, three It is a focus detection point selection subroutine that detects a focus detection point closest to the object distance from the defocus amount signal and outputs a signal corresponding to the focus detection point, and outputs a focus detection point signal SEL.

STEP 04: The defocus amount for the focus adjustment is determined from the signals of the defocus amounts of the three focus detection points and the above-mentioned focus detection point signal SEL, and the AFCNTL 30 adjusts the focus of the photographing lens.

STEP05: From AECKT17, a signal corresponding to the brightness of 15 small areas is fetched as a digital signal.

STEP06: This is a photometry mode selection subroutine that takes in the input signal from AESW18 and outputs the photometry mode signal MODE as the photometry mode according to the will of the photographer. In the present embodiment, since the photometric mode is selectively determined by the photographer, either one of the evaluation photometry and the partial photometry, the photometric mode input by the photographer, that is, the signal corresponding to the evaluation photometry or the partial photometry is used. The signal MODE is output as is. Although different from the present embodiment, when a photometric device in which the camera automatically determines the photometric mode is assumed, a signal corresponding to the photometric mode selected here is output.

STEP07: Correct the signal captured from AECKT17 based on the information specific to the taking lens captured from LROM29, and output the luminance signal of the field corresponding to each small area. Is a photometric value calculation subroutine for performing a calculation determined based on the focus detection point signal STL and the photometric mode signal MODE described above, and outputs a photometric value E.

STEP08: Based on a program preset in the camera, the shutter time and aperture value are determined from the photometric value E and output. Depending on the will of the photographer, in addition to the program mode, it is possible to switch shooting modes such as shutter priority mode and aperture priority mode. In either case,
Based on these programs, the shutter speed and aperture are determined here.

STEP09: Exposure information of shutter speed and aperture value, focus detection point selection information, photometry mode selection information, etc. as necessary
It is displayed on the display device of the camera by DPCNTL25.

STEP10: Based on the shutter time determined as described above and the aperture value, STCNTL26 controls the shutter time, and APCNTL31 controls the aperture of the taking lens.

In STEP02 to STEP10 described above, a series of shooting operations in the camera is ended, and the state returns to STEP02 to prepare for the next shooting operation.

Next, each subroutine will be described.

FIG. 6 is a flow chart showing the STEP03 focus detection point selection subroutine of FIG.

STEP11: Focus detection point selection subroutine STEP12: Import focus detection point selection information from AFSW20. AFS
W20 outputs the focus detection point selection signal AUTO when the photographer sets the focus detection point to be automatically selected by the camera, and when the photographer selectively sets one focus detection point, the photographing operation is performed. When the focus detection point S _L located on the left side of the screen is selected, the focus detection point selection signal FL is output, and when the focus detection point S _C located at the center of the shooting screen is selected, the focus detection point selection signal FC When the focus detection point S _R located on the right side of the shooting screen is selected, the focus detection point selection signal FR is output.

STEP 13: Determine whether the focus detection point selection signal is AUTO. If it is AUTO, proceed to STEP14. If it is not AUTO, proceed to STEP15.

STEP14: When the focus detection point selection signal is AUTO, AFCKT19
From the three focus detection points S _L , S _C , and S _R , the focus detection point with the shortest subject distance is identified using the signal of the defocus amount output from the signal, and the signal corresponding to the focus detection point is identified. Outputs Nearest (FL, FC, FR). When a plurality of focus detection points are equidistant and are detected as short distances, the signal FC of the center focus detection point S _C is output.

STEP 15: The focus detection point signal SEL is determined according to the focus detection point determined by the photographer's selection or the camera's automatic selection. The focus detection point signal SEL outputs any one of FL, FC and FR.

STEP16: Return to the main routine.

FIG. 7 is a flow chart showing the STEP06 photometric mode selection subroutine of FIG.

STPE21: Photometric mode selection subroutine.

STEP22: Import the metering mode selection information from AESW18. AES
W is a switch for the photographer to select either evaluative metering or partial metering, and outputs output signal EV when evaluative metering is selected and output signal PA when partial metering is selected. To do.

STEP23: Output EV or PA which is the output signal of AESW as the metering mode signal MODE as it is. In the present embodiment, the selection of the photometric mode is determined only by the photographer's will, so the photometric mode signal MODE outputs the input signal from the photometric mode selection switch AESW as it is.

STEP24: Return to the main routine.

FIG. 8 is a flow chart showing the STEP07 photometric value calculation subroutine of FIG.

STEP31: Photometric value calculation subroutine.

Step 32: Capture the digital signals D ₀₁ , D ₀₂ , D ₀₃ , ..., D ₁₅ corresponding to the brightness of 15 small areas output from AECKT17.

STEP33: Import the information specific to the attached shooting lens from LROM33. The information unique to the taking lens includes the open F number of the taking lens, the focal length, the position of the exit pupil, and the information on the amount of peripheral light drop when the diaphragm is opened.

STEP34: 15 from AECKT using information specific to the shooting lens
Correction data δ ₀₁ for correcting each output signal,
δ ₀₂ , ..., δ ₁₅ are determined, and the luminance signal for each small area is calculated. That is, the brightness signals V ₀₁ , V ₀₂ , ..., V ₁₅ are obtained from the following equation V ₀₁ = D ₀₁ + δ ₀₁ V ₀₂ = D ₀₂ + δ ₀₂ :: V ₁₅ = D ₁₅ + δ ₁₅ and output. The correction data δ ₀₁ , δ ₀₂ , ...,
It is assumed that δ ₁₅ is selected and determined from a table stored in advance in the ROM 23 based on the above-mentioned information specific to the taking lens. It is also possible to calculate by calculation.

STEP 35: It is determined whether the focus detection point signal SEL is the signal FL representing the focus detection point on the left side of the shooting screen. If SEL = FL, proceed to STEP37. If SEL ≠ FL, proceed to STEP36.

Step 36: It is judged whether or not the focus detection point signal SEL is the signal FC representing the focus detection point at the center of the shooting screen. If SEL = FC, proceed to STEP38. If SEL ≠ FC, proceed to STEP39.

According to STEP35 and STEP36, classification is performed according to the focus detection point.If the focus detection point is on the left side, proceed to STEP37.If the focus detection point is in the center, proceed to STEP38, otherwise.
That is, when the focus detection point is on the right side, the process proceeds to STEP39.

STEP37 to STEP39 classify the 15 small areas into three middle areas, the area near the focus detection point, the area around the focus detection point, and the surrounding area around the focus detection point, and calculate the average brightness of each middle area. Calculated and output. At this time, the 15 small areas are
Be sure to classify them so that they are included in any one of the middle areas.
As the average brightness signal of each middle area, the average brightness signal of the area near the focus detection point is output as A, the average brightness signal of the surrounding area is B, and the average brightness signal of the surrounding peripheral area is output as C, respectively. .

Step 37: Determine the classification of the middle area when the left focus detection point is selected, and output the average luminance signals A, B, C of each middle area based on the following equation.

A = V ₀₇ B = (V ₀₂ ＋ V ₀₆ ＋ V ₀₈ ＋ V ₁₂ ) / 4 C ＝ (V ₀₁ ＋ V ₀₃ ＋ V ₀₄ ＋ V ₀₅ ＋ V ₀₉ ＋ V ₁₀ ＋ V ₁₁ ＋ V ₁₃ ＋ V ₁₄
+ V ₁₅₎ / 10 STEP38: determining the classification of the area in the case where the focus detecting point in the center is selected, the average luminance signal A of each middle region, B, to output based on C on the following equation.

A = V ₀₈ B = (V ₀₃ ＋ V ₀₇ ＋ V ₀₉ ＋ V ₁₃ ) / 4 C ＝ (V ₀₁ ＋ V ₀₂ ＋ V ₀₄ ＋ V ₀₅ ＋ V ₀₆ ＋ V ₁₀ ＋ V ₁₁ ＋ V ₁₂ ＋ V ₁₄
+ V ₁₅ ) / 10 STEP39: Determines the classification of the middle area when the right focus detection point is selected, and outputs the average luminance signals A, B, C of each middle area based on the following formula.

A = V ₀₉ B = (V ₀₄ ＋ V ₀₈ ＋ V ₁₀ ＋ V ₁₄ ) / 4 C ＝ (V ₀₁ ＋ V ₀₂ ＋ V ₀₃ ＋ V ₀₅ ＋ V ₀₆ ＋ V ₀₇ ＋ V ₁₁ ＋ V ₁₂ ＋ V ₁₃
＋ V ₁₅ ) / 10 STEP40: Metering mode signal MODE is a signal EV that indicates evaluation metering
Or not. When MODE = EV, the process proceeds to STEP41, and when MODE ≠ EV, that is, MODE = PA, the process proceeds to STEP44.

STEP 41: Evaluative metering is selected because evaluative metering is selected as the metering mode. Using all of the average brightness signal A in the middle area near the focus detection point, the average brightness signal B in the surrounding middle area, and the average brightness signal C in the surrounding middle area around the focus detection points obtained in STEP37 to STEP39, The weighted average luminance signal E ₀ of substantially the entire screen, which has a high degree of importance in the vicinity of the focus detection point, is obtained from the following equation.

E ₀ = (A + B + C) / 3 In the above equation, the luminance signals A, B, and C of the three middle regions are simply added and averaged, but the area of the middle region near the focus detection point is S (A), The area of the middle region around it is S (B),
Further, if the area of the surrounding middle area is S (C), the area ratio of the three middle areas is S (A): S (B): S (C) = 1: 4: 10. Therefore, by performing this calculation, the weighted average luminance with a high degree of importance in the vicinity of the focus detection point is calculated. At this time, the priority J of the three middle areas A, B, and C
(A), J (B), and J (C) are proportional to the reciprocal of the area ratio, and J (A): J (B): J (C) = 1: 0.25: 0.1. In the following description, the calculation for obtaining E ₀ in the above equation is referred to as “focus detection point weighted average photometry”.

STEP 42: This is a correction value selection subroutine for analogizing the shooting situation and selectively determining the exposure correction value α by using the average brightness signal of the middle area and the difference between the average brightness signals obtained in STEP 37 to STEP 39. Details will be described later.

STEP 43: Automatic exposure correction is performed by adding the exposure correction value α output from the correction value selection subroutine to the focus detection point weighted average photometry E ₀ described above, and the photometric value E is calculated by the following equation.

E = E ₀ + α The photometric value E obtained by STEP41 to STEP43 is the photometric value by the evaluation photometry of this embodiment.

STEP44: When the metering mode signal is MODE ≠ EV in STEP40, that is, MODE = PA, the partial metering is selected as the metering mode, so the partial metering calculation is performed. With partial metering
Among the average luminance signals of the middle area obtained in STEP37 to STEP39, only the average luminance signal A of the middle area near the focus detection point is used, and this value is output as it is as the photometric value E. That is, E = A In this embodiment, as the middle area near the focus detection point, one light receiving small area including the focus detection point is selected in correspondence with the selection of the focus detection point. Therefore, the partial photometry becomes the luminance signal itself of this small area for light reception.

STEP 45: Return to the main routine.

As described above, in the photometric value calculation subroutine, whether the evaluation photometry or the partial photometry is selected as the photometry mode, the focus on the photometry area is linked with the selection of the focus detection point. By changing the degree or the photometric area itself, it is possible to perform an appropriate photometric value calculation that accepts the will of the photographer.

FIG. 9 is a flow chart showing the STEP42 correction value selection subroutine of FIG.

STEP51: Correction value selection subroutine.

STEP52: Using the average brightness signal A of the middle area near the focus detection point, the average accuracy signal B of the surrounding middle area, and the average brightness signal C of the surrounding middle area around the focus detection point, the brightness signals of the adjacent middle areas The difference between A and B, the difference between B and C, and ΔBA and ΔCB are calculated by the following equations.

ΔBA = B−A ΔCB = C−B STEP53: The average brightness signal C in the surrounding middle area is converted into a signal K corresponding to a predetermined brightness (here, it is discriminated whether it is an outdoor situation or an indoor situation). Compared with the value of about),
Recognize the approximate brightness of the scene. The reason why the average brightness signal C of the peripheral middle region is used here is that it is not affected by the reflectance of the main subject and is most suitable for inferring the situation where the main subject is placed. When C ≧ K, that is,
If it is judged that the situation is outdoors, proceed to STEP 54 and C
When <K, that is, when it is determined that the indoor situation, it proceeds to STEP71.

STEP54: When the average brightness of the surrounding middle area is higher than the predetermined value K and it is judged that the scene is an outdoor scene, first, the brightness difference ΔBA.
_Is compared with a predetermined value P _H1 having a positive sign. If ΔBA <P _H1 , proceed to STEP55, and if ΔBA ≧ P _H1 , proceed to STEP56.

Step 55: When ΔBA <P _H1 , further compare ΔBA with a predetermined value P _H2 having a negative sign. If ΔBA <P _H2 , proceed to STEP 60. If ΔBA ≧ P _H2 , that is, P _H2 ≦ ΔBA <P _H1 , S
Continue to TEP58.

The brightness difference ΔBA is classified into the following three types according to STEP54 and STEP55.

P _H1 ≦ ΔBA; ΔBA is a positive value with a large absolute value P _H2 ≦ ΔBA <P _H1 ; ΔBA is a small absolute value.

ΔBA <P _H2 ; ΔBA is a negative value with a large absolute value.

Step 56: If P _H1 ≤ ΔBA, then ΔCB is further compared with a predetermined value Q _H1 having a positive sign. If ΔCB <Q _H1 , proceed to STEP57, and if ΔCB ≧ Q _H1 , proceed to STEP62.

Step 57: If ΔCB <Q _H1 , further compare ΔCB with a predetermined value Q _H2 having a negative sign. If ΔCB <Q _H2 , proceed to STEP 64, and if ΔCB ≧ Q _H2 , that is, if Q _H2 ≦ ΔCB <Q _H1 , S
Continue to TEP63.

The brightness difference ΔCB is classified into the following three types according to STEP56 and STEP57.

Q _H1 ≤ ΔCB; ΔCB has a large absolute value Q _H2 ≤ ΔCB <Q _H1 ; ΔCB has a small absolute value.

ΔCB <Q _H2 ; ΔCB is a negative value with a large absolute value.

STEP58: When P _H2 ≤ ΔBA <P _H1 , further compare ΔCB with a predetermined value Q _H1 having a positive sign. If CB <Q _H1 , STEP65
Go to step 59 if ΔCB ≧ Q _H1 .

Step 59: When ΔCB <Q _H1 , further compare ΔCB with a predetermined value Q _H2 having a negative sign. If ΔCB <Q _H2 , proceed to STEP67. If ΔCB ≧ Q _H2 , that is, if Q _H2 ≦ ΔCB <Q _H1 , then S
Continue to TEP66.

According to STEP58 and STEP59, the brightness difference ΔCB is classified into the same three types as those performed in STEP56 and STEP57.

Step 60: When ΔBA <P _H2 , further compare ΔCB with a predetermined value Q _H1 having a positive sign. If ΔCB <Q _H1 , proceed to STEP 68. If ΔCB ≧ Q _H1 , proceed to STEP 61.

Step 61: When ΔCB <Q _H1 , further compare ΔCB with a predetermined value Q _H2 having a negative sign. If ΔCB <Q _H2 , proceed to STEP 70. If ΔCB ≥ Q _H2 , that is, if Q _H2 ≤ ΔCB <Q _H1 , STE
Continue to P69.

The brightness difference ΔCB can be calculated by STEP60 and STEP61.
It is divided into the same 3 categories as the one done in.

When it is determined in STEP53 that the scene is an outdoor scene, as described above, in STEP54 to STEP61, the situation of the scene is classified into nine types and the exposure correction value α is selected.

STEP62 to STEP70: Output the exposure correction value α suitable for the field situation classified by STEP54 to STEP61. α
In this embodiment, only three values α _H1 , α _H2, and 0 are set as the values of α _H1 <α _H2 <0, and any one of these three values is selected. . The method of determining the exposure correction value α will be described later.

STEP71: The average brightness of the surrounding middle area is lower than the predetermined value K,
When it is determined that the scene is an indoor scene, first the brightness difference Δ
Compare BA with a predetermined value P _L1 having a positive sign. If ΔBA <P _L1 , proceed to STEP72, and if ΔBA ≧ P _L1 , proceed to STEP73.

Step 72: When ΔBA <P _L1 , further compare ΔBA with a predetermined value P _L2 having a negative sign. If ΔBA <P _L2 , proceed to STEP77. If ΔBA ≧ P _L2 , that is, P _L2 ≦ ΔBA <P _L1 , S
Continue to TEP75.

The brightness difference ΔBA is classified into the following three types according to STEP71 and STEP72.

P _L1 ≤ ΔBA; ΔBA is a positive value with a large absolute value.

P _L2 ≤ ΔBA <P _L1 ; ΔBA has a small absolute value.

ΔBA <P _L2 ; ΔBA is a negative value with a large absolute value.

STEP73: When P _L1 ≦ ΔBA, further compare ΔCB with a predetermined value Q _L1 having a positive sign. If ΔCB <Q _L1 , proceed to STEP 74. If ΔCB ≧ Q _L1 , proceed to STEP 79.

Step 74: If ΔCB <Q _L1 , further compare ΔCB with a predetermined value Q _L2 having a negative sign. If ΔCB <Q _L2 , proceed to STEP81. If ΔCB ≧ Q _L2 , that is, if Q _L2 ≦ ΔCB <Q _L1 , S
Continue to TEP80.

The brightness difference ΔCB is classified into the following three types according to STEP73 and STEP74.

Q _L1 ≤ ΔCB; ΔCB is a positive value with a large absolute value.

Q _L2 ≤ ΔCB <Q _L1 ; ΔCB has a small absolute value.

ΔCB <Q _L2; ΔCB negative values greater in absolute value.

STEP75: When P _L2 ≤ ΔBA <P _L1 , further compare ΔCB with a predetermined value Q _L1 having a positive sign. STEP76 when ΔCB <Q _L1
Proceed to step 82, and if ΔCB ≧ Q _L1 , proceed to step 82.

Step 76: If ΔCB <Q _L1 , further compare ΔCB with a predetermined value Q _L2 having a negative sign. If ΔCB <Q _L2 , proceed to STEP84. If ΔCB ≧ Q _L2 , that is, if Q _L2 ≦ ΔCB <Q _L1 , S
Continue to TEP83.

Brightness difference ΔCB is calculated by STEP75 and STEP76.
It is divided into the same 3 categories as the one done in.

STEP77: When ΔBA <P _L2 , further compare ΔCB with a predetermined value Q _L1 having a positive sign. If ΔCB <Q _L1 , proceed to STEP78, and if ΔCB ≧ Q _L1 , proceed to STEP85.

Step 78: If ΔCB <Q _L1 , further compare ΔCB with a predetermined value Q _L2 having a negative sign. If ΔCB <Q _L2 , proceed to STEP 87. If ΔCB ≧ Q _L2 , that is, if Q _L2 ≦ ΔCB <Q _L1 , proceed to STEP 86.

Brightness difference ΔCB can be calculated by STEP77 and STEP78.
It is divided into the same 3 categories as the one done in.

When it is determined in STEP53 that the scene is an indoor scene, as described above, in STEP71 to STEP78, the situation of the scene is classified into nine types and the exposure correction value α is selected.

STEP79 to STEP87: Output the exposure correction value α suitable for the field situation classified by STEP71 to STEP78. α
In the present embodiment, only three values α _L1 , α _L2 and 0 are set as the values of α _L1 (where α _L1 <0 <α _L2 ) and any one of these three values is selected. . A method of determining the exposure correction value α will be described later.

STEP 88: Return to the photometric value calculation subroutine.

In the correction value selection subroutine, the situation of the object scene is analogized as described above and an appropriate correction value α is output.

Next, a method of determining the exposure correction value α will be described. 18 classified into STEP62 to STEP70 and STEP79 to STEP87 in FIG.
If the above states are represented on the coordinate plane having ΔBA and ΔCB as both coordinate axes, they are as shown in FIGS. 10 (a) and 10 (b). Also,
The states of STEP62 to STEP70 and STEP79 to STEP87 in FIG. 9 are 11th when the luminance signals A, B and C of the respective middle regions are shown by a bar graph.
It becomes as shown in FIGS. FIG. 11 also schematically shows the focus detection point weighted average photometric value E ₀ , the exposure correction value α, and the evaluation photometric value E in each situation.
The situation of the object scene under each condition and the method of determining the exposure correction value α will be described below with reference to FIGS. 10 and 11.

(A) When K ≦ C: Outdoor scene (ai) P _H1 <ΔBA, Q _H1 <ΔCB (STEP62) As shown in FIG. 10 (a), ΔBA is greater than a predetermined positive value P _H1 . If ΔCB is larger than a predetermined positive value Q _H1 , the first
This is the case of the brightness distribution as shown in (i) of FIG. In such a case, since the background part has high brightness and the main subject part has relatively low brightness, it can be generally estimated that the scene is a backlight scene. Moreover, since the luminance signal A, the luminance signal B, and the luminance signal C are changed in a stepwise manner, the main subject arranged near the focus detection point has an area for outputting the luminance signal A and an area for outputting the luminance signal B. It is thought that it exists for a part of. In the case of such a brightness distribution, the focus detection point weighted average photometric value E ₀ is an output as shown in the figure, but while sufficiently considering the brightness of the main subject described above,
Considering the background brightness to some extent, in order to give a proper exposure, the correction value α _H1 with a negative sign and a relatively large absolute value is used.
It is preferable to output the evaluation photometric value E as shown in FIG. 11 (a) (i).

(A-ii) P _H1 <ΔBA, Q _H2 <ΔCB ≦ Q _H1 (STEP63) As shown in FIG. 10 (a), ΔBA is larger than the positive predetermined value P _H1 , and ΔCB is the negative predetermined value Q _{This is the} case where it is larger than _H2 and smaller than the predetermined positive value Q _H1 , and the luminance distribution is as shown in (ii) of FIG. 11 (a). In such a case as well, it can be estimated that it is a backlight scene as in the case of (i).
Focusing on the variation in the luminance signal, it is considered that only the luminance signal A has a relatively low luminance, and the main subject is arranged only in the area that outputs the luminance signal A. Also,
In such a case, the size of the main subject may be approximately the same as the area where the luminance signal A is output, or may be slightly smaller than this area. In the former case, the luminance difference ΔBA appears relatively large. In the latter case, the luminance signal A itself is already affected by the background luminance, and the luminance difference ΔBA
Is relatively small. In any case, when it is detected that the brightness difference ΔBA is larger than the predetermined positive value P _H1 and a relatively low-brightness main object is located near the focus detection point, the focus as shown in the figure is displayed. With respect to the detection-point-weighted average photometry value E ₀ , the brightness of the main subject is fully taken into consideration, the brightness of the background is also taken into account, and the evaluation value is measured using the correction value α _H1 that is approximately the same as in (i) It is good to output the value E.

(A-iii) P _H1 <ΔBA, ΔCB ≤ Q _H2 (STEP64) As shown in Fig. 10 (a), ΔBA is larger than a predetermined positive value P _H1 and ΔCB is smaller than a negative predetermined value Q _H2. If in the first
This is the case of the brightness distribution as shown in (iii) of FIG. Such a brightness distribution appears when a high-brightness subject is locally present in the area where the brightness signal B is output. In such a case, if the correction is performed so as to eliminate the influence of this local high-brightness subject, it becomes possible to give a suitable exposure to the entire screen. Therefore, in FIG.
As shown in i), it is preferable to output the evaluation photometric value E using the correction value α _H2 having a negative sign and a relatively small absolute value.

(A-iv) P _H2 <ΔBA ≤ P _H1 , Q _H1 <ΔCB (STEP65) As shown in Fig. 10 (a), ΔBA is larger than the negative predetermined value P _{H2 and} is larger than the positive predetermined value P _H1 . This is the case where ΔCB is small and ΔCB is larger than a predetermined positive value Q _H1 , and the luminance distribution is as shown in (iv) of FIG. 11 (a). In such a case as well, it can be estimated that it is a backlight scene as in the case of (i).
Focusing on the variation of the luminance signal, the luminance signal A and the luminance signal B have lower luminance than the luminance signal C, and the main subject is referred to as an area outputting the luminance signal A and an area outputting the luminance signal B. It is thought that they are distributed over a fairly wide area. In the case of such a brightness distribution, it is better to output a photometric value that places more importance on the area determined to be the main subject, but the focus detection point-weighted average photometric value E ₀ has a slightly high brightness as shown in the figure. Since it is affected by the brightness of the background area, it is preferable to output the evaluation photometric value E using the correction value α _H2 that is substantially the same as that in (iii).

(Av) P _H2 <ΔBA ≤ P _H1 , Q _H2 <ΔCB ≤ Q _H1 , (STEP66) As shown in Fig. 10 (a), ΔBA is larger than a predetermined negative value P _H2 and positive. When the luminance difference is smaller than the predetermined value P _H1 , ΔCB is larger than the negative predetermined value Q _H2 and smaller than the positive predetermined value Q _H1 , and the brightness difference is small as shown in (v) of FIG. 11 (a). Is. Such a brightness distribution is (i
In the backlight scene where the size of the main subject becomes even smaller in the scene similar to the case of i) and it becomes difficult to detect the brightness of the main subject part, and in the scene similar to the case of (iv), the main subject It is assumed that the size of the image becomes even larger and a landscape scene or the like in which a substantially entire screen is the main subject. Even in a backlit scene where the main subject is small, it is better to handle it as a backlit scenery scene under such a situation. Therefore, the focus detection point weighted average photometry is set to 0 for the correction value so as to give proper exposure to the entire screen. It is better to use the value E _{0 as it} is as the evaluation photometric value E.

(A-vi) P _H2 <ΔBA ≤ P _H1 , ΔCB ≤ Q _H2 (STEP67) As shown in Fig. 10 (a), ΔBA is larger than the negative predetermined value P _H2 and larger than the positive predetermined value P _H1 . This is the case where ΔCB is small and ΔCB is smaller than the negative predetermined value Q _H2 , and the luminance distribution is as shown in (vi) of FIG. 11A. Such a brightness distribution appears in the area where the brightness signal A is output and in the brightness signal B.
This is the case where a main subject having a considerably high luminance is arranged in both of the areas for outputting, and in many cases, with respect to the luminance signal C indicating the general brightness as described above, the main subject having a considerably high luminance is displayed. The subject is a subject with high reflectance (whitish). Therefore, in such a case, as shown in the figure, the main subject part is depicted as whitish (ii
Evaluative photometric value E using the correction value α _H2 that is almost the same as in case i)
Is good to output.

(A-vii) ΔBA ≦ P _H2 , Q _H1 <ΔCB (STEP68) As shown in FIG. 10 (a), ΔBA is smaller than the negative predetermined value P _H2 and ΔCB is larger than the positive predetermined value Q _H1. If in the first
This is the case of the brightness distribution as shown in (vii) of FIG. Such a brightness distribution appears when the main subject itself has a considerable contrast ratio or a landscape scene with a special composition, but it is not a general scene and the frequency is also low. Few. In such a case, it is preferable to give a proper exposure to the entire screen. As in the case of (v), the correction value is set to 0, and the focus detection point weighted average photometry value E ₀ is evaluated as it is. It is good to output as the value E.

(A-viii) ΔBA ≦ P _H2 , Q _H2 <ΔCB ≦ Q _H1 (STEP69) As shown in FIG. 10 (a), ΔBA is smaller than the negative predetermined value P _H2 and ΔCB is the negative predetermined value Q. _When it is larger than _H2 and smaller than a predetermined positive value Q _H1 , (viii) in FIG. 11 (a).
This is the case of the brightness distribution as shown in. In such a case, as in the case of (vi), it can be estimated that the main subject is a subject with high reflectance (whitish). Further, in such a case, it can be determined that the size of the main subject portion is smaller than that in the case of (vi). In the case of such an object, it is necessary to depict the main object part whitish to some extent, but if the focus detection point weighted average photometric value E ₀ is used as it is, it is possible to give almost the desired exposure. Therefore, it is preferable to output the evaluation photometric value E using the correction value 0.

(A-ix) ΔBA ≤ P _H2 , ΔCB ≤ Q _H2 (STEP 70) As shown in Fig. 10 (a), ΔBA is smaller than the negative predetermined value P _H2 and ΔCB is smaller than the negative predetermined value Q _H2. If in the first
This is the case of the luminance distribution as shown in (ix) of FIG. In such a case, it is estimated that the subject is the same as in (vi), and the size of the main subject can be determined to be an intermediate size between (vi) and (viii).
Further, in such a case, the area near the focus detection point has higher brightness than in the cases of (vi) and (viii),
It can be determined that a subject having a higher reflectance is placed or a light source is placed. In such a case, even if the focus detection point weighted average photometric value E ₀ is used as it is, the main subject part is depicted as whitish to some extent, but the main subject part is considered in consideration of the balance with the peripheral part of the screen. To make the image more whitish, (ii
It is preferable to output the evaluation photometric value E by using the correction value α _H2 that is substantially the same as i).

(B) When C <K: Indoor scene (b-i) P _L1 <ΔBA, Q _L1 <ΔCB (STEP79) As shown in FIG. 10 (b), ΔBA is larger than a predetermined positive value P _L1. , ΔCB is larger than a predetermined positive value Q _L1 ,
This is the case of the luminance distribution as shown in (i) of FIG. In such a case, the background part is not very bright and the main subject part is considerably lower in brightness than the background part, so that the main subject is placed in a position where it is not illuminated by the illumination light in the room. Scenes etc. are assumed. In addition, a scene in which a subject having a slightly low reflectance (blackish) is arranged near the focus detection point is also assumed. Further, it is considered that the size of the main subject exists in the area where the luminance signal A is output and a part of the area where the luminance signal (b) is output as in the case of (a-i). Under such conditions, in order to depict the situation of the object scene observed by the photographer according to the sense of the photographer, the main subject portion does not have to reproduce its detail portion.
It is desirable to give exposure that is described as a little black. Therefore, as shown in (i) of FIG. 11 (b),
It is preferable to obtain the evaluation photometric value E by using a correction value α _L1 having a negative sign and a relatively small absolute value with respect to the focus detection point weighted average photometric value E ₀ .

(B-ii) P _L1 <ΔBA, Q _L2 <ΔCB ≤ Q _L1 (STEP80) As shown in Fig. 11 (b), ΔBA is larger than the positive predetermined value P _L1 and ΔCB is the negative predetermined value Q. _The case where it is larger than _L2 and smaller than the positive predetermined value Q _L1 is the case of the luminance distribution as shown in (ii) of FIG. 11B. Even in such a case, it can be estimated that the main subject portion is a dark scene as in the case of (i). The size of the main subject is (a-i
Similar to i), it can be determined that it is slightly smaller than the case of (i). Even in such a case, as in the case of (i),
It is desirable to depict the main subject part in a slightly blackish color, and as shown in the figure, it is preferable to output the evaluation photometric value E using a correction value α _L1 that is substantially the same as in the case of (i).

(B-iii) P _L1 <ΔBA, ΔCB ≤ Q _L2 (STEP 81) As shown in Fig. 11 (b), ΔBA is larger than the positive predetermined value P _L1 and ΔCB is smaller than the negative predetermined value Q _L2. If in the first
This is the case of the luminance distribution as shown in (iii) of FIG. Such a brightness distribution appears when there is a locally high brightness subject such as an illumination light source in the area where the brightness signal B is output. In such a case, the focus detection point weighted average photometric value E ₀ is influenced by this high-brightness region and renders the main subject part slightly black, which provides a suitable exposure for such a scene. As shown in the figure, it is preferable to set the correction value to 0 and output the focus detection point weighted average photometric value E ₀ as the evaluation photometric value E as it is.

(B-iv) P _L2 <ΔBA ≤ P _L1 , Q _L1 <Δ CB (STEP82) As shown in Fig. 10 (b), ΔBA is larger than the negative predetermined value P _L2 and the positive predetermined value P _When LCB is smaller than _L1 and ΔCB is larger than a predetermined positive value Q _L1 , (iv) in FIG. 11 (b).
This is the case of the brightness distribution as shown in. Even in such a case, it can be estimated that the main subject portion is a dark scene as in the case of (i). The size of the main subject is (a-i
Similar to (v), it can be determined that it is larger than that of (i) and is arranged over a fairly wide area of the shooting screen. Even in such a case, it is desirable to depict the main subject part in a slightly blackish manner as in the case of (i), but as shown in the figure, the focus detection point weighted average photometry value E ₀ gives a fairly suitable exposure as it is. Since these values are set, it is preferable to set the correction value to 0 and output the focus detection point weighted average photometry value E _{0 as it} is as the evaluation photometry value.

(B-v) P _L2 <ΔBA ≤ P _L1 , Q _L2 <Δ CB ≤ Q _L2 (STEP83) As shown in Fig. 10 (c), ΔBA is larger than a negative predetermined value P _L2 and is a positive predetermined value. When the brightness difference is smaller than the value P _L1 and ΔCB is larger than the negative predetermined value Q _L2 and smaller than the positive predetermined value Q _L1 , and the brightness difference is small as shown in (v) of FIG. 11 (b). is there. Such a brightness distribution appears in the same situation as (av), but in an indoor scene, in particular, a bright part and a dark part are mixed in each region, and the brightness signals A, B, and C are output as the middle region. At this time, there are not a few scenes in which the brightness difference is small as a result. In such a case, as in (av), the correction value is set to 0 so as to give proper exposure to the entire screen, and the focus detection point weighted average photometric value E ₀ is output as it is as the evaluation photometric value E. Is good.

(B-vi) P _L2 <ΔBA ≤ P _L1 , ΔCB ≤ Q _L2 (STEP 84) As shown in Fig. 10 (b), ΔBA is larger than the negative predetermined value P _L2 and is also the positive predetermined value P _L1. When it is smaller and ΔCB is smaller than the predetermined negative value Q _L2 , it is the case of the luminance distribution as shown in (vi) of FIG. 11B. Such a brightness distribution appears because the main subject exists in both the area outputting the brightness signal A and the area outputting the brightness signal B, the main object is illuminated by the illumination light, and the other background area is present. For example, when the brightness is relatively high. In such a case, in order to give a suitable exposure that gives importance to the main subject portion while giving some consideration to the luminance signal of the background portion, as shown in the drawing, the correction value α with a positive sign _It is preferable to output the evaluation photometric value E using _L2 .

(B-vii) ΔBA ≦ P _L2 , Q _L1 <ΔCB (STEP85) As shown in FIG. 10 (b), ΔBA is smaller than the negative predetermined value P _L2 and ΔCB is smaller than the positive predetermined value Q _L1 . In case of big,
This is the case of the luminance distribution as shown in (vii) of FIG. 11 (b). Such a brightness distribution appears (a-vii)
Similar to the above, there is a special situation, and in this case (a-vi
It is preferable to give proper exposure to the entire screen as in the case of i). Therefore, the correction value is set to 0, and the focus detection point weighted average photometric value E ₀ is output as it is as the evaluation photometric value E. good.

(B-viii) ΔBA ≦ P _L2 , Q _L2 <ΔCB ≦ Q _L1 (STEP86) As shown in FIG. 10 (b), ΔBA is smaller than the negative predetermined value P _L2 , and ΔCB is the negative predetermined value Q. _When it is larger than _L2 and smaller than a predetermined positive value Q _L1 , (vii in FIG. 11B).
This is the case of the brightness distribution as shown in i). In such a case, as in the case of (vi), it can be estimated that only the main subject portion has a relatively high brightness due to illumination light or the like. Also, the size of the main subject portion can be determined to be smaller than that in the case of (vi) from the distribution state of the luminance signal. In such a case, in order to give an exposure in which the luminance signal of the main subject portion is emphasized and the luminance signal of the background is also taken into consideration to some extent, the focus detection point-weighted average photometry value E _{0 is set} to (v
Evaluation photometric value E using the correction value α _L2 that is almost the same as in case i)
Is good to output.

(B-ix) ΔBA ≦ P _L2 , ΔCB ≦ Q _L2 (STEP87) As shown in FIG. 10 (b), ΔBA is smaller than a predetermined negative value P _L2 and ΔCB is smaller than a predetermined negative value Q _L2. If in the first
This is the case of the brightness distribution as shown in (ix) of FIG. In such a case, it is estimated that the subject is the same as that in the case of (vi), and the size of the main subject can be determined to be an intermediate size between the case of (vi) and the case of (viii). . Further, in such a case, compared to the cases of (vi) and (viii), the area near the focus detection point has higher brightness, and the main object illuminated by the illumination light or the like has a slightly higher reflectance. It is assumed that the scene is a high (slightly whitish) subject, or a lighting light source is arranged behind or in the vicinity of the main subject. In such a case, the area near the focus detection point is described as a little whitish, and the exposure considering the balance of the entire screen is given while giving importance to the main subject portion, as shown in (v
It is preferable to output the evaluation photometric value E using the correction value α _L2 that is substantially the same as in the case of i).

As described above, in this embodiment, the situation of the object scene is set to 18
It is configured so that the optimum exposure correction value α is selectively determined under each condition. The relationship between the magnitudes of the exposure correction values described above can be summarized as follows.

α _H1 <α _H2 <0 α _L1 <0 <α _L2 Also, regarding the magnitude relationship between α _H1 or α _H2 and α _L1 ,
Depending on the setting of the predetermined values P _H1 , P _H2 , Q _H1 , Q _H2 , P _L1 , P _L2 , Q _L1 , and Q _L2 , when the brightness differences ΔBA and ΔCB are approximately equal values, it is generally It is desirable that _H2 <α _L1 .

In the method of determining the exposure correction value α described above, in order to simplify the description, the classification of the field based on the brightness differences ΔBA and ΔCB is 9
I went through the streets one by one, but see, for example, Figure 11 (a) and (b).
In particular, in a situation where the selection result of the exposure correction value α greatly changes according to the brightness difference, such as the classification of the states (ii) and (v), a more detailed classification is performed. It is desirable to do so. Further, it is desirable to perform more detailed classification even in the case of classifying the object scene based on the luminance signal c. By categorizing the object field more closely in this way, it is possible to obtain stable exposure by reducing the exposure unevenness when the shooting composition changes slightly.

The photometric device configured to output a proper photometric value by advancing the situation of the field using the above-mentioned luminance signal differences ΔBA and ΔCB and the luminance signal C in the peripheral portion of the photographing screen is the same as the applicant. JP-A-62-184319.

In addition, the focus detection point weighted average photometry in the present embodiment is a calculation for obtaining an addition average value with the importance of the luminance signal of the divided small area as a coefficient according to the position of the selected focus detection point. , When the left focus detection point is selected, the center focus detection point is selected, and the right focus detection point is selected, the coefficient of importance of each area is shown in FIGS. ), (C). It goes without saying that the combination of the coefficients of importance is not limited to this.

[Other Examples]

FIGS. 13 (a) and 13 (b) are views showing the divided shape of the photometric light receiving portion of another embodiment of the present invention. In the first embodiment of the present invention, the photometric light receiving section is divided into 15 small areas having the same shape, but may be divided into small areas having different shapes and areas as shown in FIG. However, in such a case, when classifying the luminance signals of the small areas into the middle areas, it is necessary to take care so that the area of each middle area is not significantly changed by the selection of the focus detection points.

In FIGS. 13 (a) and 13 (b), the object scene is divided into 11 small areas for photometry.
Reducing the number of divisions has the advantages of simplifying the photometric circuit and reducing the cost of the photometric light-receiving element. When the photometric light-receiving section is divided as shown in Fig. 13, the light-receiving small areas arranged in the peripheral area of the shooting screen are connected in series to reduce the effective number of photometric light-receiving sections. , Can be less. A technique for reducing the number of divisions of the light receiving portion for photometry in this manner is disclosed in Japanese Patent Application Laid-Open No. 60-125527 of the same applicant.

In the above embodiment, the reference for selecting the focus detection point is set to the shortest distance in the automatic selection mode. However, another way of thinking, for example, using the difference in the defocus amount, the intermediate focus is used. It is also possible to select a detection point.
It is also effective to prepare a plurality of types of selection criteria in advance and switch them according to the situation.

〔The invention's effect〕

The present invention, according to the selection of the focus detection region, a first region including the selected focus detection region, and a second region surrounding the first region and including a plurality of brightness detection small regions, It is divided into at least three areas of a third area that surrounds the second area and includes a plurality of small areas that are in a combination different from that of the second area, and the divided first area.
And comparing the luminance of the second region with the luminance of the second region.
Since the brightness of the area of 3 is compared with the brightness of the third area and the photometric value is calculated also by using this comparison information, it is possible to obtain an appropriate photometric value in consideration of the size of the main subject and the situation of the scene.

Further, since the divided first, second, and third areas have substantially the same area ratio even if the selection of the focus detection area is changed, the size of the main object is changed even if the position of the main object is changed. It is possible to judge the degree and the scene in almost the same manner.

[Brief description of drawings]

FIG. 1 is a diagram showing a divided shape of a photometric light receiving portion of a first embodiment of the present invention, FIG. 2 is a sectional view of an optical system of a camera of a first embodiment of the present invention, and FIG. FIG. 4 is a perspective view of a multi-point focus detection optical system of the first embodiment, FIG. 4 is a diagram showing the circuit configuration of a camera of the first embodiment of the present invention, and FIGS. 5 to 9 are the first embodiment of the present invention. FIG. 10 to FIG. 12 are explanatory views for explaining the flow chart of the first embodiment of the present invention, and FIG. 13 shows the divided shape of the photometric light receiving portion of another embodiment of the present invention. The figure to represent. 6 ... Light receiving part for photometry 15 ... Light receiving part for focus detection 22 ... Central processing unit CPU

 ─────────────────────────────────────────────────── --- Continuation of front page (56) References JP-A-62-255925 (JP, A) JP-A-1-235929 (JP, A) JP-A-1-280737 (JP, A) JP-A-1- 202720 (JP, A) JP 62-184319 (JP, A) JP 61-279829 (JP, A) JP 60-125527 (JP, A) JP 63-7330 (JP, B2) Actual public Sho 51-9271 (JP, Y2)

Claims (2)

[Claims] 1. A camera provided with a focus detection means configured to independently detect focus in a plurality of areas within a photographic screen, wherein a photometric area is divided into a plurality of small areas, and the brightness of each of the divided small areas is divided. A light receiving means for detecting the plurality of small areas into a preset combination according to the selection of the focus detection area; a first area including the selected focus detection area; A second region that surrounds the first region and includes the plurality of small regions, and a third region that includes the second region that surrounds the second region and is in a different combination from the second region. Setting means for dividing the area into at least three areas, and brightness for comparing the brightness of the first area and the second area and comparing the brightness of the second area and the third area The comparing means and the light receiving means A camera that uses the obtained brightness of each small area and also calculates a photometric value by using each comparison information obtained by the brightness comparing means. 2. The first and the first divided by the setting means
The second and third regions are different combinations of the above small regions according to the selection of the focus detection region, and
The camera according to claim 1, wherein the cameras are divided into areas having substantially equal area ratios.