JP2004012614A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera which can judge backlight without disturbance even under difficult conditions for photographing such as near the limit of the photometric range. <P>SOLUTION: The camera as one aspect of the invention is equipped with a sensor array which can detect the luminance signal of the object and has a plurality of regions for detection of the focus, a first photometry means to calculate the luminance signal of the object from the output of the sensors in a single or a plurality of regions in the above sensor array, a second photometry means which can detect the luminance signal of the object in a wider range than the detection of the luminance signal of the object by the above sensor array, and a judging means to judge whether the use of the first photometry means can be inhibited or not according to the output of the second photometry means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a camera, and more particularly, to a camera having a backlight determination function.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a camera having a backlight determination function, a camera that measures the luminance of a main subject with a photometric sensor and detects backlight is known.
[0003]
Conventionally, as a camera having a backlight determination function, in an area AF camera, the brightness of a main subject selected by the AF sensor is measured by the AF sensor and compared with the overall average brightness of the AE sensor to determine the backlight. Cameras adapted to perform such operations are known.
[0004]
That is, in such a camera, different sensors are used for the AF sensor and the AE sensor for their original purposes.
[0005]
In addition, since the dynamic range required for photometry is considerably wide, each sensor is often designed with a value just below the dynamic range required for normal photographing.
[0006]
[Problems to be solved by the invention]
By the way, in the camera according to the conventional technique as described above, the photometric range is inevitably different between two different sensors.
[0007]
In particular, AF sensors generally have a method of integrating the photocurrent of the sensor and obtaining the subject brightness by the time required to reach the threshold level. Therefore, in the case of high brightness, the photocurrent is large and the threshold level is reduced. The time to reach is short, and the photometric range on the high luminance side is small.
[0008]
At this time, there is a problem that accurate backlight detection cannot be performed under photographic conditions that are at the very end of the photometric range or beyond, and erroneous backlight detection is performed.
[0009]
For example, in a subject region where the subject brightness exceeds the photometry-capable brightness limit value of the AF sensor, but is within the photometry-capable range of the AE sensor, the AF sensor exceeds the measurement limit. Is output, and accurate backlight determination cannot be performed, and there is a problem that the backlight is erroneously determined to be backlight even though it is not actually backlight.
[0010]
The present invention has been made in view of the above circumstances, and in a system for detecting back light by an AF sensor and an AE sensor, if a photometric value of at least one sensor is equal to or more than a predetermined luminance, the backlight is not detected. Accordingly, it is an object of the present invention to provide a camera capable of performing a backlight determination without any inconvenience even under a photographing condition at the very end of a photometry range of one sensor.
[0011]
[Means for Solving the Problems]
According to the present invention, in order to solve the above problems,
(1) a sensor array having a plurality of regions for focus detection capable of detecting a luminance signal of a subject;
First photometric means for calculating a luminance signal of the subject from sensor outputs of one or more regions of the sensor array;
A second photometric unit capable of detecting a subject luminance signal in a wider range than the detection of the subject luminance signal by the sensor array;
Judging means for judging whether or not use of the first photometric means can be prohibited according to an output from the second photometric means;
There is provided a camera comprising:
[0012]
(Action)
The AF sensor spot metering is prohibited according to the brightness of the metering sensor.
[0013]
According to the present invention, in order to solve the above problems,
(2) Exposure means for photographing a subject;
A sensor array having a plurality of regions for focus detection, which can detect the luminance signal of the subject,
First photometric means for calculating a luminance signal of the subject from sensor outputs of one or more regions of the sensor array;
A second photometric unit capable of detecting the luminance signal of the subject in a wider range than the detection of the luminance signal of the subject by the sensor array;
Whether or not to change the exposure amount for photographing the subject according to whether or not the difference between the luminance signal from the first photometer and the luminance signal from the second photometer is greater than a predetermined value. Determining means for determining
A camera is provided, wherein the determination unit changes the determination of the exposure amount according to an output of the first photometry unit.
[0014]
(Action)
The threshold level of the backlight determination is changed according to the brightness of the photometric sensor.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a block diagram showing a configuration of a main part of a camera according to an embodiment of the present invention.
[0017]
FIG. 1 is a block diagram of a so-called lens shutter type silver halide camera for photographing a subject image entered from a photographing lens 8 on a film 10 by opening and closing a shutter 19.
[0018]
The CPU 1 is a control means composed of, for example, a one-chip microcomputer for controlling the sequence of the entire camera.
[0019]
The CPU 1 performs a process for photographing in a predetermined sequence according to an operation on the switch input unit 13 by the photographer.
[0020]
As a distance measuring means for measuring the distance of the subject 17, subject image signals obtained through two light receiving lenses 2a and 2b arranged at a distance of the base line length B are photoelectrically converted by a pair of sensor arrays 3a and 3b. The digital image signal is obtained by A / D conversion by the A / D conversion means 4.
[0021]
The CPU 1 obtains a relative position difference X between the image input signals by comparing the pair of digital image signals.
[0022]
That is, the relative position difference X changes in a relationship of X = BF / L depending on the subject distance L, the focal length F of the light receiving lenses 2a and 2b, and the base line length B. Thus, the focusing distance L can be calculated.
[0023]
The sensor arrays 3a and 3b are, for example, a non-TTL-AF type and extend in the horizontal direction of the camera, and monitor the area 23a when aiming at a subject shis as shown in FIG. .
[0024]
The entire monitor area 23a is divided into 13 blocks as shown in FIG. 3A, and the above-described X detection is performed using the image signal of each block, thereby measuring 13 points on the screen. Distance becomes possible.
[0025]
Of the thirteen distance measurement signals obtained in this manner, for example, the one indicating the closest distance is set as the main subject distance.
[0026]
A photographing optical system including a photographing lens 8 which is a zoom lens, a distance measuring optical system (light receiving lenses 2a and 2b), and a photometric optical system (AE lens 5) are separately provided.
[0027]
When the photographer operates an operation member (not shown), the CPU 1 drives the focal length of the photographing lens 8 via the zoom drive circuit 14 and moves the focal length of the photographing lens 8 from the wide-angle side to the telephoto side, thereby changing the angle of view and the field of view of the photographing. The configuration can be changed.
[0028]
The camera is provided with a finder optical system 20 for a photographer to check a photographing screen.
[0029]
The finder optical system 20 is configured to operate in conjunction with the focal length of the taking lens 8.
[0030]
That is, as the CPU 1 moves the focal length of the photographing lens 8 from the wide-angle side to the telephoto side via the zoom drive circuit 14, the finder optical system 20 is also driven, and the focal length changes from the wide-angle side to the telephoto side. .
[0031]
The finder field of view is designed to be in the same range as the field of view of the photographing lens 8 irrespective of the focal length, and the photographer can recognize the photographing range (field of view) by looking into the finder optical system 20. it can.
[0032]
As described above, since the photographing optical system and the distance measuring optical system are provided separately, for example, when the photographing lens 8 is on the wide-angle side, the photographing field of view is 24 W shown in FIG. The field of view of 3b is like 23a.
[0033]
Further, when the taking lens 8 is on the telephoto side, the taking visual field is 24T shown in FIG. 2, whereas the ranging optical system is a fixed lens that is not linked to the focal length of the taking lens 8. Since the field of view of the sensor arrays 3a and 3b does not change, the relationship between the imaging field of view and the distance measurement field of view is as shown in 24T and 23a.
[0034]
When the field of view is 24W in FIG. 2, as shown in FIG. 3A, 13 points of multi-point AF (multi-AF) are performed in 13 areas of the distance measuring sensor 23a.
[0035]
In the case where the photographing visual field is like 24T in FIG. 2, as shown in FIG. 3B, 7 points AF (multi-AF) is performed in 7 out of 13 points of the distance measuring sensor 23a like the distance measuring sensor 23b. )I do.
[0036]
As shown in FIG. 1, split-type photometric sensors 6a and 6b that receive light passing through the AE lens 5 are provided.
[0037]
The outputs of the photometric sensors 6a and 6b are converted by an AE circuit 21 composed of a logarithmic compression circuit, and the brightness in the photographing screen is measured. Based on the result, the CPU 1 controls the exposure.
[0038]
This photometric optical system is also provided separately from the optical system of the photographing lens 8, and is not linked to the focal length of the photographing lens 8.
[0039]
Therefore, the fields of view when the photographing lens 8 is wide-angle and telephoto are 24 W and 24 T, respectively, and the relationship between the fields of view 26 a and 26 b of the photometric sensors 6 a and 6 b is as shown in FIG. 2.
[0040]
Therefore, when the photographing lens 8 is telephoto, the output from the sensor 6a is used, and when the photographing lens 8 is wide-angle, the sum of the output from the sensor 6a and the output from the sensor 6b is used, so that photometry of a portion almost the same as the photographing visual field is performed. Can be.
[0041]
Each of the distance measurement points divided into 13 as shown in FIGS. 3A and 3B is composed of strip-shaped pixels as shown in FIG. Since the data is output according to the shadow, image data as shown in FIG. 3D is obtained.
[0042]
By averaging the image outputs obtained in this way, an average luminance at each ranging point is obtained.
[0043]
With such a configuration, the position of the main subject can be detected by the multi-AF, and the brightness at that position can be obtained. Therefore, the main subject can be detected based on the processing flow shown in FIG. It is possible to take a picture by the exposure control with emphasis.
[0044]
The details of photometry using the distance measurement sensors 3a and 3b will be described later.
[0045]
Based on the results of the multi-AF distance measurement, the CPU 1 controls the photographing lens 8 via a photographing lens control circuit (LD) 9 to focus on the subject, and to measure the light measurement results of the distance measurement sensors 3a and 3b and the light measurement sensor. By controlling the opening and closing of the shutter 19 using the photometric results in 6a and 6b, it is possible to perform shooting by exposure control with emphasis on the main subject.
[0046]
At the time of the exposure control, the CPU 1 controls the strobe circuit 15 as necessary to cause the strobe 16 to emit light.
[0047]
Next, a specific example in which the above-described configuration is used for a zoom lens camera having a variable focal length from 35 mm to 80 mm will be described with reference to FIGS. 4 and 5.
[0048]
FIG. 5 is a flowchart shown to explain a specific sequence.
[0049]
FIG. 4 is a diagram for explaining the relationship between the brightness BVSP of the distance measurement sensor, the value of the brightness BVAVG of the photometry sensor, and the light emission when the sequence of FIG. 5 is executed.
[0050]
First, photographing is started when the photographer operates the operation member 13.
[0051]
In step S101, the zoom position is detected, and the current focal length of the photographing lens 8 is detected.
[0052]
In step S102, the focal length detected in step S101 is stored in a variable ZM.
[0053]
In step S103, it is determined from the variable ZM whether or not the focal length of the photographing lens 8 is more than 50 mm. If it is on the telephoto side, the process proceeds to step S104, and if it is on the wide-angle side, the process proceeds to step 105.
[0054]
In step S104, since the focal length of the photographing lens 8 is on the telephoto side, only the output from the above-described photometric sensor 6a is used as the photometric sensor for average photometry.
[0055]
Then, the average brightness value of the entire photographic screen obtained from the output of the photometric sensor 6a is stored in a variable BVAVG.
[0056]
In step S105, since the focal length of the photographing lens 8 is on the wide angle side, the average value of the output from the above-described photometric sensor 6a and the output from the photometric sensor 6b is used as the average photometric sensor.
[0057]
Then, the average brightness value of the entire photographic screen obtained from the outputs of the photometric sensors 6a and 6b is stored in a variable BVAVG.
[0058]
In steps S106 and S107, when the focal length is on the wide-angle side, the distance measurement points near the main subject are obtained from the 13 distance measurement points when the focal length is on the telephoto side. (Details of which are omitted in the description of FIGS. 1 to 3), and the main subject distance is calculated using a distance measurement sensor near the point of the main subject.
[0059]
In step S108, the point of the main subject is stored in a variable n (here, since there are 13 distance measurement points, n is any one of values 1 to 13).
[0060]
In step S109, the luminance near the main subject is measured using the distance measurement sensors 3a and 3b near the main subject.
[0061]
That is, since the variable n-th is the distance measurement sensor near the point of the main subject, the brightness of the n-point AF sensor is measured.
[0062]
In step S110, the spot brightness of the main subject obtained by the main subject photometry in step S104 is stored in the variable BVSP.
[0063]
In step S111, the photographing lens 8 is driven so that the object distance obtained in step S106 is in focus.
[0064]
In step S112, it is determined from the average photometric luminance of the entire screen obtained in step S109 or step S110 whether the screen is dark and the strobe 16 needs to emit light.
[0065]
Specifically, BVAVG is compared with the camera shake luminance value according to the focal length. If BVAVG is smaller, the process proceeds to step S116, and if not, the process proceeds to step S113.
[0066]
In step S113, it is determined from the average photometric brightness of the entire screen obtained in step S109 or step S110 whether the brightness is equal to or higher than a predetermined brightness.
[0067]
Specifically, BVAVG is compared with a predetermined brightness BV (BV13). If BVAVG is smaller, the process proceeds to step S114, and if not, the process proceeds to step S115.
[0068]
Here, in the embodiment of the present invention, the photometric range of the sensors 3a and 3b for distance measurement is BV2 to BV13 (this corresponds to EV7 to EV18 when converted to an EV value in the case of ISO100). ).
[0069]
When a high luminance exceeding BV13 enters, the distance measuring sensors 3a and 3b output an indefinite value.
[0070]
When the values of the spot distance measuring sensors 3a and 3b are used as photometry for backlight detection at the time of high luminance, the output from the photometric sensor 6a or the output from the photometric sensors 6a and 6b is used as in step S113. By judging whether or not to use the outputs of the distance measurement sensors 3a and 3b for photometry according to the value of BVAVG, which is the sum, it is possible to avoid using a photometry value that exceeds the photometry range of the distance measurement sensors 3a and 3b. Control.
[0071]
In step S114, it is determined from the main subject luminance obtained in step S107, step S109 or step S110 and the average photometric luminance of the entire screen whether or not the subject is backlit.
[0072]
Specifically, BVAVG-BVSP is executed, and if the luminance difference is larger than one step, it is determined that the subject is backlit, and the process proceeds to step S116; otherwise, the process proceeds to step S115.
[0073]
In step S115, the shutter is controlled with an aperture value corresponding to the brightness value of BVAVG to expose the film 10.
[0074]
In step S116, the shutter is controlled with the aperture value according to the brightness value of BVAVG, or the shutter is controlled with the aperture value according to the camera shake brightness, and the exposure to the film 10 is performed. The flash 16 is emitted via the flash circuit 15 to make the exposure proper or to make the whole screen dark.
[0075]
In step S117, since the exposure of the film 10 has been completed, the film 10 is wound up by one frame, and the processing ends.
[0076]
Note that, when the above-described sequence of FIG. 5 is executed, the relationship between the value of the brightness BVSP of the distance measurement sensors 3a and 3b, the value of the brightness BVAVG of the photometry sensors 6a and 6b, and the light emission is shown. In FIG. 4, the horizontal axis represents the brightness BVAVG of the photometric sensors 6a and 6b, and the vertical axis represents the brightness BVSP of the main subject in the distance measuring sensors 3a and 3b.
[0077]
In FIG. 4, a region A indicates a low-luminance automatic light-emitting region that emits light according to the low-luminance determination in step S112 described above.
[0078]
An area B indicates an automatic backlighting area that emits light based on the backlight determination in step S114 described above.
[0079]
Further, a region C indicates a non-light-emitting region that does not emit light depending on whether or not to perform the backlight detection in step S113 described above.
[0080]
That is, according to the specific example described above, it is determined whether or not the luminance range of the distance measuring sensors 3a and 3b can be used according to the photometric values of the photometric sensors 6a and 6b. And 3b are not used outside the range of the photometry of the distance measuring sensor, so that an erroneous backlight determination is not performed.
[0081]
Next, another specific example in which the above configuration is used for a zoom lens camera having a variable focal length from 35 mm to 80 mm will be described with reference to FIGS.
[0082]
FIG. 7 is a flowchart shown to explain the sequence of this another specific example.
[0083]
FIG. 6 is a diagram illustrating the relationship between the brightness BVSP of the distance measurement sensor, the value of the brightness BVAVG of the photometry sensor, and the light emission when the sequence of FIG. 7 is executed.
[0084]
First, photographing is started when the photographer operates the operation member 13.
[0085]
In step S200, the ISO sensitivity of the film 10 is detected, converted into an SV value, and stored in a variable SV.
[0086]
In step S201, the zoom position is detected, and the current focal length of the photographing lens 8 is detected.
[0087]
In step S202, the focal length detected in step S201 is stored in a variable ZM.
[0088]
In step S203, it is determined from the variable ZM whether or not the focal length of the photographing lens 8 is more than 50 mm. If it is on the telephoto side, the process proceeds to step S204, and if it is on the wide angle side, the process proceeds to step 205.
[0089]
In step S204, since the focal length of the taking lens is on the telephoto side, only the output of the above-described photometric sensor 6a is used as the photometric sensor for average photometry.
[0090]
Then, the average brightness value of the entire photographic screen obtained from the output of the photometric sensor 6a is stored in a variable BVAVG.
[0091]
In step S205, since the focal length of the photographing lens is on the wide-angle side, the average value of the outputs from the photometric sensors 6a and 6b is used as the photometric sensor for average photometry.
[0092]
Then, the average brightness value of the entire photographic screen obtained from the outputs of the photometric sensors 6a and 6b is stored in a variable BVAVG.
[0093]
In step S206, a distance measuring point close to the main subject is selected from the 13 distance measuring points (the details are omitted in FIGS. 1 to 3).
[0094]
In step S207, the subject distance is calculated using a distance measurement sensor near the point of the main subject.
[0095]
In step S208, the point of the main subject is stored in a variable n (here, the distance measuring point is 13 points in telephoto and 7 points in wide angle, so n is one of values of １３13).
[0096]
In step S209, the luminance of the vicinity of the main subject is measured using the output of n points of the distance measurement sensor near the main subject.
[0097]
In step S210, the spot brightness of the subject obtained by main subject photometry at n points of the distance measurement sensor is stored in the variable BVSP.
[0098]
In step S211, the photographic lens 8 is driven via the photographic lens drive circuit (LD) 9 so as to focus on the subject distance obtained in step S207.
[0099]
In step S212, it is determined from the average photometric brightness of the entire screen obtained in step S204 or step S205 whether the screen is dark and the flash 16 needs to emit light.
[0100]
Specifically, the camera shake EV value corresponding to the focal length is compared with the sum of BVAVG and SV. If the sum of BVAVG and SV is smaller, the process proceeds to step S218; otherwise, the process proceeds to step S216. I do.
[0101]
In step S213, it is determined from the average photometric luminance of the entire screen obtained in step S204 or step S205 whether or not the luminance is equal to or higher than a predetermined luminance.
[0102]
Specifically, BVAVG is compared with the predetermined brightness BV13. If BVAVG is smaller, the process proceeds to step S214, and if not, the process proceeds to step S215.
[0103]
In step S214, it is determined from the main subject luminance obtained in step S207, step S209, or step S210 and the average photometric luminance of the entire screen whether or not the subject is backlit.
[0104]
Specifically, BVAVG-BVSP is executed, and if the luminance difference is larger than two steps, it is determined that the subject is backlit, and the flow shifts to step S218; otherwise, the flow shifts to step S217.
[0105]
In step S215, it is determined whether the average photometric luminance of the entire screen obtained in step S204 or S205 is equal to or higher than a predetermined luminance.
[0106]
Specifically, BVAVG is compared with the predetermined brightness BV5, and if BVAVG is larger, the process proceeds to step S214, and if not, the process proceeds to step S216.
[0107]
In step S216, it is determined from the main subject luminance obtained in step S217, step S209 or step S210 and the average photometric luminance of the entire screen whether or not the subject is backlit.
[0108]
Specifically, BVAVG-BVSP is executed, and if the luminance difference is larger than one step, it is determined that the subject is backlit, and the process proceeds to step S218; otherwise, the process proceeds to step S217.
[0109]
Here, in the embodiment of the present invention, the light meterable range of the sensors 3a and 3b for distance measurement is BV0 to BV15 (this corresponds to EV5 to EV21 when converted to an EV value in the case of ISO100). .
[0110]
However, the distance measuring sensors 3a and 3b have poor linearity between the high-luminance side and the low-luminance side, and an error increases in high-luminance exceeding BV13 or low-luminance below BV5.
[0111]
For this reason, in the embodiment of the present invention, when using the values of the distance measurement sensors 3a and 3b as the photometry for backlight detection at the time of high luminance or low luminance, steps S213, S214, and S215 are used. The distance measurement sensors 3a and 3b are changed by changing the threshold value for judging backlight as in step S216, and setting the threshold value for judging backlight in a range where the photometric error is small to 2 EV compared to 1 EV. To prevent erroneous backlight determination due to a photometric error.
[0112]
In step S217, the exposure to the film 10 is performed by controlling the shutter 19 with the aperture value corresponding to the brightness value of BVAVG.
[0113]
In step S218, the shutter 19 is controlled with an aperture value corresponding to the brightness value of BVAVG, or the shutter 19 is controlled with an aperture value corresponding to the camera shake EV value, so that exposure to the film 10 is performed and backlight is controlled. The strobe 16 is emitted via the strobe circuit 15 in order to make the exposure of a certain main subject proper or to make the whole screen dark.
[0114]
In step S219, since the exposure of the film 10 has been completed, the film 10 is wound up by one frame, and the processing ends.
[0115]
Note that, when the above-described sequence of FIG. 7 is executed, the relationship between the luminance BVSP of the distance measurement sensors 3a and 3b, the luminance BVAVG of the photometry sensors 6a and 6b, and the light emission is shown. In FIG. 6, the horizontal axis represents the brightness BVAVG of the photometric sensors 6a and 6b, and the vertical axis represents the brightness BVSP of the distance measuring sensors 3a and 3b.
[0116]
In FIG. 6, regions A and D indicate low-luminance automatic light-emitting regions that emit light based on the above-described low-luminance judgment.
[0117]
In the present embodiment, the low-luminance automatic light-emitting area is calculated from the ISO sensitivity, the camera shake shutter time according to the focal length, and the aperture value according to the focal length.
[0118]
For example, in the present embodiment, the low-luminance automatic light-emitting area is ISO100, BV5 and area D + A for wide, and ISO400 and BV3 and area D + A for wide.
[0119]
A region B indicates a backlight automatic light emission region that emits light based on the above-described backlight determination.
[0120]
Further, a region C indicates a non-light-emitting region where no light is emitted due to the above-described low luminance determination and backlight determination.
[0121]
That is, according to another specific example as described above, the threshold value of the backlight determination using the photometric sensors 6a, 6b and the distance measuring sensors 3a, 3b is changed according to the photometric values of the photometric sensors 6a, 6b. Therefore, accurate backlight detection can be performed even in a luminance region where the error of the distance measurement sensors 3a and 3b is relatively large.
[0122]
In the present embodiment, the distance measuring sensor is divided into 13 blocks as distance measuring points. However, the present invention is also applicable to the case where the output of the distance measuring sensor in various other divided forms is used for photometry of the main subject. It is possible.
[0123]
Further, in the present embodiment, a ranging sensor having a one-dimensional ranging point is used. For example, an output of a multi-ranging sensor capable of measuring a two-dimensional area is used for main subject photometry. It is also applicable to cases.
[0124]
In the present embodiment, a camera using a silver halide film is described. However, the present invention can be applied to, for example, a digital camera in which a shooting optical system and a distance measuring optical system are different.
[0125]
Further, in the present embodiment, the photometric value of the main subject is used for backlight detection. For example, a photometric value of an area other than the main subject of the distance measuring sensor or the entire screen is measured using a similar configuration. It may be used only when exposure correction is performed based on the photometric value of.
[0126]
Further, in this embodiment, the main subject photometry value using a part of the distance measurement sensor and the average photometry value of the entire screen using the photometry sensor are used for determining the exposure. However, the present invention is not limited to this. For example, a configuration may be used in which a main subject photometric value using a part of the distance measuring sensor and a photometric value of the entire screen using the entire distance measuring sensor are used to determine the exposure.
[0127]
Further, in the present embodiment, the photometry and the backlight detection are all examples of the auto mode in which the camera performs. However, for example, the present invention is also applicable to a configuration in which a distance measurement sensor is used for spot photometry.
[0128]
【The invention's effect】
Therefore, as described above, according to the present invention, in a system for detecting backlight with the AF sensor and the AE sensor, the backlight detection is not performed when the photometric value of the AE sensor is equal to or higher than a predetermined luminance. In a system for detecting backlight with a multipoint AF sensor and a divided AE sensor, if the photometric value of at least one AE sensor is equal to or higher than a predetermined luminance, the backlight is not detected, so It is possible to provide a camera that can perform backlight determination without any inconvenience even under shooting conditions.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a main part of a camera according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a relationship between a shooting visual field and a distance measuring visual field;
FIG. 3 is a diagram illustrating a relationship between distance measurement points by a distance measurement sensor and a relationship between obtained image data;
FIG. 4 is a diagram illustrating a relationship between a luminance BVSP of a distance measuring sensor, a value of a luminance BVAVG of a photometric sensor, and light emission when the sequence of FIG. 5 is executed.
FIG. 5 is a flowchart illustrating a sequence of a specific example in which the present invention is used in a zoom lens camera having a variable focal length from 35 mm to 80 mm.
FIG. 6 is a diagram illustrating a relationship between a luminance BVSP of a distance measuring sensor, a value of a luminance BVAVG of a photometric sensor, and light emission when the sequence of FIG. 7 is executed.
FIG. 7 is a flowchart illustrating a sequence of another specific example in which the present invention is used in a zoom lens camera having a variable focal length from 35 mm to 80 mm.
[Explanation of symbols]
8. Photographing lens (photographing optical system)
10 ... film,
1 ... CPU,
13 switch input means,
14. Zoom drive circuit,
19 ... Shutter,
20: finder optical system,
6a, 6b: photometric sensor,
21 ... AE circuit,
15 ... Strobe circuit,
16 ... Strobe.

Claims (2)

A sensor array having a plurality of regions for focus detection, which can detect a luminance signal of a subject,
First photometric means for calculating a luminance signal of the subject from sensor outputs of one or more regions of the sensor array;
A second photometric unit capable of detecting a subject luminance signal in a wider range than the detection of the subject luminance signal by the sensor array;
Judging means for judging whether or not use of the first photometric means can be prohibited according to an output from the second photometric means;
A camera comprising: Exposure means for photographing the subject;
A sensor array having a plurality of regions for focus detection, which can detect the luminance signal of the subject,
First photometric means for calculating a luminance signal of the subject from sensor outputs of one or more regions of the sensor array;
A second photometric unit capable of detecting the luminance signal of the subject in a wider range than the detection of the luminance signal of the subject by the sensor array;
Whether or not to change the exposure amount for photographing the subject according to whether or not the difference between the luminance signal from the first photometer and the luminance signal from the second photometer is greater than a predetermined value. Determining means for determining
2. The camera according to claim 1, wherein the determination unit changes the determination of the exposure amount according to an output of the first photometry unit.

Images