JP2000019582A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply execute a proper photometric calculation, in the case a focus detecting region is arranged in the vicinity of the boundary of a photometric region. SOLUTION: In this camera constituted so that in a photographic picture frame, plural photometric regions S0-S18 are formed by dividing, plural focus detecting regions F0-F8 are formed and at least one of these plural focus detecting regions is arranged in the vicinity of the division boundary of the photometric regions (for instance, on a division boundary), when the focus detecting region selected by a focus detecting region selecting means is one in the vicinity of the division boundary, the detected luminance of the plural photometric regions divided by the boundary is compared to decide a main photometric region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera which divides a photographing screen (field) into a plurality of small areas and performs photometry.

[0002]

2. Description of the Related Art Conventionally, various cameras have been proposed in which an object scene is divided into a plurality of regions and a proper exposure is given to a photographing screen by using a luminance signal for each of these regions.

For example, in Japanese Patent Laid-Open Publication No. Hei 3-223821, a field is divided into a plurality of areas, and the luminance of each area is detected. The plurality of photometric sub-regions are grouped concentrically around the selected focus detection region in accordance with the selection of the focus detection region in the detection means, and a predetermined weight is assigned to each average luminance of the grouped regions. A camera has been proposed which calculates the photometric value of the entire object scene by using the camera.

Japanese Patent Application Laid-Open No. 5-53169 discloses a configuration in which the position of a subject in an object scene is input by detecting the position of the line of sight of a photographer, while the C for photometry is used.
A camera is proposed in which a large number of pixels of a CD image sensor are grouped into a plurality of patterns according to a division pattern that flexibly changes according to the position of the subject, and a predetermined weight is applied to the average luminance of each group to obtain a photometric value. Have been.

By the way, in order to obtain a large amount of luminance information from the object scene, the photometric sensor tends to be divided into multiple parts in order to photograph the object scene with an optimum exposure amount. For example, as in the camera proposed in JP-A-5-53169, CC
By using an area sensor such as D, it is possible to obtain an optimal divided photometric pattern for a subject.

However, since the area sensor is a charge accumulation type sensor, it has a problem of responsiveness at the time of low luminance, and its price is expensive. For this reason, a photodiode type sensor is generally widely used as a photometric sensor.

However, for this photodiode type sensor, increasing the number of divisions of the sensor section means that the light receiving area of each divided small area is reduced, and consequently the photometric capability of the photometric sensor at low luminance. Means lowering. Therefore, it is better to use a divided sensor having a certain size and number than to use an area sensor composed of an aggregate of sensors having a minute size as a photometric sensor capable of forming an arbitrary number of fine divided patterns. It can be said that the sensor is generally easy to use from the viewpoint of low luminance photometric capability and photometric computation processing capability.

On the other hand, a camera performs a focus detection operation in order to focus a photographic lens on a photographic subject. Sensors that perform this focus detection also tend to be multi-divided. For example, by using two area sensors and dividing the pixels of the area sensor to obtain correlations, a large amount of the image in the photographing screen is obtained by a known phase difference detection method. Can be detected.

The contents proposed so far for the relationship between the photometry area and the distance measurement area are described in Japanese Patent Laid-Open No. Hei 3-2238.
Since the number of focus detection areas is considerably smaller than the number of photometric areas in each of the cameras including the camera proposed in Japanese Patent Publication No. 21, it is possible to arrange each focus detection area substantially at the center of gravity of each of the small photometric areas. Was. Therefore, if a photometry operation such as a weighting operation is performed based on the determination that the photometry region including the focus detection region where the focus detection (distance measurement) operation is to be performed is a photometry region corresponding to the main subject position, it is almost appropriate. I was able to get a good exposure.

However, if the number of focus detection areas can be configured to be equal to or smaller than the number of photometric small areas, the focus detection area where the focus detection operation of the main subject should be performed is determined. It becomes difficult to arrange the photometric sub-region almost at the position of the center of gravity, and it becomes impossible to determine a single photometric small region corresponding to the main subject position as a reference for performing photometric calculation. In other words, this means that an accurate exposure cannot be determined for the photographing subject. Such optical inconsistency, which can be called parallax between the focus detection area and the photometric small area, arises from a difference in the sensor layout shape between the focus detection sensor and the photometric sensor itself, or a problem in the optical configuration.

[0011]

In order to solve this problem, the applicant of the present invention proposes that if a focus detection area on the boundary between two photometric sub-areas is selected as a focus detection area to be subjected to focus detection, the two photometric areas will be detected. A camera has been proposed in which two weighting calculations are performed on a small area with each photometry small area as the center, and an exposure value is determined from both calculations.

However, in this method, the exposure value is averaged with a photometric calculation value that emphasizes the luminance of the photometric small area irrelevant to the original main subject position, and the luminance of the original main subject is reduced. On the other hand, there is a possibility that the effect of the weighting operation for performing the maximum weighting becomes weak.

Further, the applicant of the present invention has proposed a method in which the amount of defocus in the focus detection area on the boundary between the two selected photometric small areas and the two focus detection areas corresponding to the photometric small area divided by the boundary. The proposed method also compares the defocus amount of the selected focus detection area with the selected focus detection area and selects a photometric small area corresponding to the focus detection area indicating the defocus amount closest to the defocus amount and performs a weighted photometric calculation. ing.

However, in this method, it is necessary to perform a computationally heavy operation of comparing the defocus amount in terms of software, and the defocus amount is low in a region where the focus detection operation is to be performed because of low brightness and low contrast. Cannot be calculated, there is also a disadvantage that the photometric calculation does not operate correctly as a result.

Accordingly, the present invention provides a method for detecting a small number of divided photometric areas even when the focus detection area in which the focus detection operation of the main subject is to be performed by the viewfinder optically is located near the boundary between the small photometric areas. It is an object of the present invention to provide a camera capable of performing optimal photometry using only a luminance signal, centering on a main subject, and taking the entire object field into consideration.

[0016]

In order to achieve the above-mentioned object, according to the present invention, a plurality of photometric areas are divided and a plurality of focus detection areas are formed in a photographing screen. In a camera in which at least one of the plurality of focus detection areas is arranged near a division boundary of the photometry area (for example, on the division boundary), the focus detection area selected by the focus detection area selection means is a focus near the division boundary. When the area is the detection area, the main photometry area is determined by comparing the detection luminances of a plurality of photometry areas divided by the boundary.

Specifically, an area having the lowest detected luminance is selected from the plurality of photometric areas divided by the boundary as the main photometric area, and the detected luminance of the main photometric area is weighted with the maximum weight. The photometric calculation may be performed.

Thus, when the focus detection area arranged near the division boundary is selected as the area where the focus detection operation is to be performed, it is possible to determine the photometry area serving as a reference for the photometry calculation. It is possible to obtain an appropriate exposure result using a photometric sensor having a relatively small number of divisions.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 to 6 show a single-lens reflex camera according to a first embodiment of the present invention. In this figure, reference numeral 1 denotes a photographing lens, which is shown as a two-lens lens for the sake of convenience in this drawing, but is actually composed of a larger number of lenses. Reference numeral 2 denotes a main mirror, which is obliquely provided in the photographing optical path in the viewfinder system observation state, and retreats from the photographing optical path in the photographing state.

Reference numeral 3 denotes a sub-mirror, which reflects a light beam transmitted through the main mirror 2 downward of the camera body. Reference numeral 4 denotes a shutter.

Reference numeral 5 denotes a photosensitive member, which comprises a silver halide film, a solid-state image pickup device such as a CCD or MOS type, or an image pickup tube such as a vidicon.

Reference numeral 6 denotes a focus detection device, which includes a field lens 6a and reflection mirrors 6b and 6 arranged near the image plane.
c, a secondary imaging lens 6d, an aperture 6e, and a plurality of CCDs
And a line sensor 6f.

The focus detecting device 6 of the present embodiment uses a known phase difference method, and as shown in the viewfinder view of FIG. 3, a plurality of focus detecting areas F in a photographing screen (field).
The focus state can be detected at 0 to F8 (corresponding to the focus detection area marks 70 to 78).

Reference numeral 7 denotes a focusing plate arranged on a predetermined image forming plane of the photographing lens 1, and 8 denotes a pentaprism for changing a finder optical path.

Reference numerals 9 and 10 denote an imaging lens and a photometric sensor for measuring the luminance of each object in the photographing screen, respectively. The imaging lens 9 is connected to the focus plate 7 and the photometric sensor via a reflection optical path in a pentaprism 8. 10 is related to the conjugate.

Here, as shown in FIG. 3, the photometric sensor 10 can detect the luminance of each small area (photometric small area) which divides the photographing screen into 19 areas S0 to S18. Small area sensors (SPC-0 to SPC-1)
8) A 19-split sensor.

Here, as shown in FIG. 3, the focus detection areas F0, F2, F4, F6, and F8 are respectively arranged so as to be located substantially at the centers of gravity of the small photometric areas S3, S1, S0, S2, and S4. And the focus detection areas F1, F3, F
5, F7 are photometric small areas S3-S1, S1-S, respectively.
0, S0-S2, and S2-S4. Note that the boundary line of each photometric small area in the finder field of view shown in FIG. 3 is a virtual line that is obtained by projecting the divided state of the photometric sensor on the finder, and these lines cannot be seen in an actual finder. .

An eyepiece 11 is arranged behind the exit surface of the pentaprism 8, and is used for observing the focus plate 7 with the eyes of the photographer.

The main mirror 2, the focus plate 7, the pentaprism 8, and the eyepiece 11 constitute a finder optical system.

Reference numeral 21 denotes a high-brightness LED which can be visually recognized even in a bright subject, and has a light emission center wavelength of 680 nm red.

Reference numeral 22 denotes an LCD in which the positions of the nine focus detection areas are patterned (hereinafter referred to as SI-LCDs), which correspond to the positions where the focus detection areas are selected from these SI-LCDs. Only those patterns that are in the transmissive state. Light emitted from a superimposing LED (hereinafter, referred to as SI-LED) 21 behind the SI-LCD 22 passes only through the transmission pattern of the SI-LCD 22, and is transmitted through the light projecting lens 23 and the dichroic mirror-2.
The light reaches the eyeball of the photographer via the eyepiece 11 via 4. This allows the photographer to visually check the focus detection area display pattern on the finder screen. That is, as can be seen from the viewfinder field view shown in FIG.
Patterns 70 to 78 corresponding to focus detection areas F0 to F8
Is illuminated in the viewfinder field, and the selected focus detection area can be displayed in a superimposed manner.

Here, the dichroic mirror 24 has a characteristic of reflecting light having a wavelength of 680 nanometers or more, efficiently guides the light of the SI-LED 22 to the eyes of the observer, and also controls the light from the photographing lens. The photographer can observe the image as a finder field image with almost no light quantity decrease.

Reference numeral 25 denotes a finder LCD (hereinafter, referred to as F-LCD) for displaying photographing information outside the photographing screen in the finder visual field, and an illumination LED (hereinafter, referred to as F-LCD).
F-LED) 26. F-
The light transmitted through the LCD 25 is guided by the triangular prism 27 to the outside of the photographing screen as shown in FIG. This allows the photographer looking through the viewfinder to know various types of photographing information. 28 is a shutter speed display,
Reference numeral 29 denotes an aperture value display segment, and reference numeral 30 denotes a focusing mark indicating the focusing state of the photographing lens 1.

In FIG. 1, reference numeral 31 denotes an aperture provided in the taking lens 1, reference numeral 32 denotes an aperture driving device including an aperture driving circuit 111 described later, reference numeral 33 denotes a lens driving motor, and reference numeral 34 denotes a lens comprising a driving gear and the like. It is a driving member.

Reference numeral 35 denotes a photocoupler, which detects the rotation of the pulse plate 36 interlocked with the lens driving member 34 and transmits this information to the lens focus adjustment circuit 110. The focus adjustment circuit 110 drives the lens driving motor 33 by a predetermined amount based on this information and the information on the lens driving amount from the camera side, and moves the photographing lens 1 to the focusing position.

Reference numeral 37 denotes a mount contact serving as an interface between the camera and the lens.

FIG. 2 shows a configuration of an electric circuit built in the single-lens reflex camera. Central processing unit (hereinafter referred to as CPU) of a microcomputer built in the camera body
100), a photometry circuit 102, an automatic focus detection circuit 103, a signal input circuit 104, an LCD drive circuit 10
5. LED drive circuit 106, shutter control circuit 108
And the motor control circuit 109 are connected. Further, signals are transmitted to the focus adjustment circuit 110 and the aperture drive circuit circuit 111 disposed in the taking lens via the mount contact 37 shown in FIG.

EEPROM 10 attached to CPU 100
0a has a storage function of storing various adjustment data.

The photometric circuit 102 includes 19 small area sensors SPC-0 to SPC-
After amplifying the 18 luminance signals, logarithmic compression and A / D conversion are performed, and transmitted to the CPU 100 as luminance information of each sensor.

The line sensor 6f comprises nine sets of line sensors CCD-0 to CCD-8 corresponding to the nine focus detection areas 70 to 78 in the finder screen.
It is a D line sensor.

The automatic focus detection circuit 103 A / D converts the voltage obtained from the line sensor 6f,
Send to

SW-1 (12) is the first release button.
A photometric switch that is turned on by a stroke operation (half-press operation) to start photometric and AF operations. SW-2 (13)
Is the second stroke operation of the release button (full press operation)
This is a release switch that is turned ON with. SW-DIAL1
And SW-DIAL2 (15) are dial switches provided in an electronic dial (not shown). Signals from these switches are input to an up / down counter of a signal input circuit 104, and the signal input circuit 104 rotates the electronic dial. Count clicks.

Signals from these switches are input to the signal input circuit 104, and the data is transferred to the CPU 100 by the data bus.
Sent to.

Reference numeral 105 denotes an LCD drive circuit for driving the liquid crystal display element LCD to display an aperture value, a shutter speed, a set photographing mode, and the like according to signals from the CPU 100. -L
SI-LCD2 for CD25 and superimpose
2 are simultaneously controlled so as to be displayed on the display unit 2.

The LED drive circuit 106 includes the F-LED 26
And the SI-LED 21 is turned on and off.

The shutter control circuit 108 controls the magnet MG-1 for running the front curtain and the magnet MG-2 for running the rear curtain when energized, so that the photosensitive member 5 is exposed to a predetermined amount of light.

When the photosensitive member 5 is a film, the motor control circuit 109 controls a motor M1 for winding and rewinding the film and a motor M2 for charging the main mirror 2 and the shutter 4. The shutter control circuit 108 and the motor control circuit 109 operate a series of camera release sequences.

Next, the operation of the entire camera of this embodiment will be described.
This will be described with reference to the flowchart of FIG. Here, the case where the shutter priority AE is set will be described.

When the camera is set from the inoperative state to a predetermined photographing mode, the power of the camera is turned on (step # 1).
00), the camera waits until the release button is pressed and the switch SW1 (12) is turned on (step # 101).

When the release button is depressed and the switch S
When the CPU 100 detects that W1 has been turned on through the signal input circuit 104, the CPU 100 performs mutual communication with a lens mounted on the camera, and obtains lens information necessary for the camera to perform photometry and AF, for example, photographing. Opening F of lens 1
NO. Then, information such as the best focus position and the like is transferred to the memory of the camera (step # 102).

Next, nine sets of line sensors CCD-0 to C are provided.
The CD-8 starts the operation of accumulating the field light, and calculates defocus amounts (image shift amounts) DEF0 to DEF8 in the respective sensors corresponding to the current shooting screen (step # 103).

Next, in order to perform the focus detection operation, it is confirmed whether the focus detection area selection switch 14 is OFF or ON, that is, whether the focus detection area selection mode is the automatic mode or the manual mode (step). # 10
4).

Here, when the automatic mode is set, the defocus amount D in the nine focus detection areas is set.
Based on EF0 to DEF8, a specific focus detection area is selected by a focus detection area automatic selection subroutine (step # 105). Several methods can be considered as an algorithm for automatic selection of a focus detection area. For a multipoint AF camera, a near-point priority algorithm in which a weight is assigned to a central focus detection area is effective.

When the manual mode is set, the photographer can freely select one of the nine focus detection areas by operating the switch dial 15 (step # 106). Thus, one focus detection area is determined automatically or manually (step # 107).

Next, in the determined focus detection area, the automatic focus detection circuit 103 performs a focus detection calculation, and determines whether the determined focus detection area is an area in which focus detection can be performed (step # 108). . Here, when the focus detection operation is disabled, the CPU 100
5 to flash the focus mark 30 on the F-LCD 24 to warn the photographer that the focus detection is NG,
On the other hand, if focus detection is possible and the focus adjustment state of the focus detection area selected by a predetermined algorithm is not in focus, C
The PU 100 sends a signal to the lens focus adjustment circuit 110 to drive the photographing lens 1 by a predetermined amount (step # 10).
9). Then, after driving the lens, it is determined whether or not the photographing lens 1 is in focus (step # 110).

When the photographing lens 1 is in focus in a predetermined distance measuring area, the CPU 100
5 to turn on the focus mark 30 of the F-LCD 25, and also to the LED drive circuit 106 to send a signal to the SI-LED corresponding to the focused focus detection area.
21 is turned on, and a segment corresponding to the focus detection area is illuminated to display an in-focus state.

At the same time, the CPU 100
2 to perform photometry (step # 1).
11). At this time, a photometric operation is performed by weighting the photometric region corresponding to the focused focus detection region. The details of the photometric operation will be described later. In the present embodiment, the photographing lens aperture value (for example, F5.6) 29 is displayed on the photometric calculation result using a segment and a decimal point.

Next, it is determined whether or not the photographer has accepted the focus state and the photometric value in the determined focus detection area in S.
The determination is made based on ON / OFF of W1 (Step # 11)
2). Further, it is determined whether or not the release button is depressed and the switch SW2 is turned on.
If W2 is in the OFF state, the state of the switch SW1 is confirmed again (step # 113). On the other hand, switch SW
When 2 is in the ON state, the CPU 100 transmits signals to the shutter control circuit 108, the motor control circuit 109, and the aperture drive circuit 111, respectively. The motor control circuit 109 energizes the motor M2 to move up the main mirror 2 and narrow down the aperture 31. Thereafter, the shutter control circuit 108 energizes the magnet MG1 to open the front curtain of the shutter 4. The aperture value of the aperture 31 and the shutter speed of the shutter 4 are determined from the exposure value detected by the photometry circuit 102 and the sensitivity of the film 5.

Then, a predetermined shutter time (1/12)
After 5 seconds, the magnet MG2 is energized, and the rear curtain of the shutter 4 is closed. When the exposure of the film 5 is completed, the motor M2 is energized again to perform mirror down and shutter charging, and the motor M1 is also energized to perform frame advance of the film, ending a series of shutter release sequence operations. (Step # 114).

After that, the camera turns on the switch SW1 again.
It waits until N is reached (Step # 101 return).

Next, the photometric calculation performed in step # 111 will be described with reference to the flowchart of FIG.

To execute the photometric calculation, the CPU 100 first takes in the outputs (subject luminance signals) of the 19 divided sensors sent from the photometric circuit of the photometric sensor 10 and performs AD conversion of the output. Do (Step # 2)
00).

Next, the open FNO. That is the lens information of the photographing lens 1 obtained by the lens communication in step # 102. The AD sensor converts the output of the divided sensor into a correct luminance signal of the photographic subject by using the data of the peripheral light amount drop and the like. Thereafter, the corrected luminance signals of these small areas S0 to S18 are referred to as e0 to e18 (step # 2).
01).

At this time, the focus detection areas in which the focus detection operation is to be performed in step # 107 are F0 to F8.
One of them. Therefore, in order to determine the photometric calculation to be performed in accordance with the determined focus detection area, it is determined whether the determined focus detection area is located substantially at the center of gravity of the photometric small area including the focus detection area. (Step # 20)
2). Specifically, when the determined focus detection area is F1, F3, F5, or F7 on the boundary between the small photometry areas, the process proceeds to step # 203.

In step # 203, the luminance signals of a plurality of photometric small areas divided by the boundary (forming a boundary) are compared with each other, and the photometric small area having the minimum luminance signal is set as the main photometric area. Determine.

Here, a case where the focus detection area F1 is determined in step # 107 will be described as an example. In this case, the photometric small areas S1 and S3 are divided by the boundary where the focus detection area F1 exists, and the magnitudes of the respective luminance signals e1 and e3 are compared. As a result, e1 <
If e3, the photometric small area e1 is determined as the main photometric area, and if e1> e3, the photometric small area e3 is determined as the main photometric area.

On the other hand, in step # 202, if the determined focus detection area is F0, F2, F4, F6, or F8 which is located substantially at the position of the center of gravity of the small photometry area, step #
Proceed to 204. In step # 204, a photometric small area having the determined focus detection area substantially at the position of the center of gravity is automatically determined as the main photometric area. For example, when the focus detection area F2 is determined in step # 107, the photometric small area S1 is determined as the main photometric area.

Next, a weighted photometric operation in which the largest weight is applied to the photometric small area (main photometric area) determined in step # 203 or # 204 is performed by the following method. The photometry calculation described here can be classified into five calculation expressions as a result because one of the five photometry small areas S0 to S4 is determined in step # 203 or step # 204.

Here, the case where the photometric small area S1 is determined as the main photometric area will be described in detail in accordance with the above example, and the case where the other photometric small areas S0, S2, S3, and S4 are determined will be described. Only the photometric calculation formula is shown.

When the photometric small area S1 is determined in step # 205, the CPU 100 converts the small photometric areas S0 to S18 into three concentric circles A, B, and C around the small photometric area S1.
Into two groups. First, only the photometric small area S1 is A
In the group, the photometric small areas S0, S3, S7, and S8, which are the areas surrounding the photometric small area S1, are grouped B, and the other photometric small areas S2, S4, S5, S6, S9 to S18.
Is set to the C group (step # 205).

Next, the groups A, B, and C are weighted in consideration of the area of each photometric small area. The approximate area ratio of each photometric small region is (S0, S1, S2, S3, S
4): (S5, S6, S7, S8, S9, S10):
(S11, S12, S13, S14): (S15, S1
6, S17, S18) = 3: 2: 4: 12,
The average luminance: EA1, EB1, EC1 of each of the above groups can be obtained as follows.

EA1 = e1 EB1 = (3 (e0 + e3) +2 (e7 + e8)) / 10 EC1 = (3 (e2 + e4) +2 (e5 + e6 + e9 + e10) +4 (e11 + e12 + e13 + e14) +12 (e15 + e16) +17 (e15 + e16 + 17) e0 to e18 are photometry small areas S0 to S, respectively.
18 is an output value of a luminance signal corresponding to No. 18.

Since the position of the main subject is considered to be in the group A, the weighting condition A: B:
By setting C = 3: 2: 1, photometry with emphasis on the main subject can be performed.

From the above, the photometric value (exposure value) E with emphasis on the main subject can be obtained by the following equation.

E = (3EA + 2EB + EC) / 6 (unit: BV) The above photometric calculation formulas (1) to (4) are applicable even if any of the photometric small areas S0 to S4 is selected as the main photometric area in step # 304. Used similarly. The calculation formula in each case is shown below. In each case, the formula is common (step # 206).

When the main photometry area is S0, EA0 = e0 EB0 = (3 (e1 + e2) +2 (e5 + e6)) / 1
0 EC0 = (3 (e3 + e4) +2 (e7 + e8 + e9 +
e10) +4 (e11 + e12 + e13 + e14) +1
2 (e15 + e16 + e17 + e18)) / 78.

When the main photometric area is S2, EA2 = e2 EB2 = (3 (e0 + e4) +2 (e9 + e10)) /
10 EC2 = (3 (e1 + e3) +2 (e5 + e6 + e7 +
e8) +4 (e11 + e12 + e13 + e14) +12
(E15 + e16 + e17 + e18)) / 78.

When the main photometry area is S3, EA3 = e3 EB3 = (3e1 + 4 (e11 + e12)) / 11 EC3 = (3 (e0 + e2 + e4) +2 (e5 + e6 +
e7 + e8 + e9 + e10) +4 (e13 + e14) +
12 (e15 + e16 + e17 + e18)) / 77.

When the main photometric area is S4, EA4 = e4 EB4 = (3e2 + 4 (e13 + e14)) / 11 EC4 = (3 (e0 + e1 + e3) +2 (e5 + e6 +
e7 + e8 + e9 + e10) +4 (e11 + e12) +
12 (e15 + e16 + e17 + e18)) / 77.

In step # 203, if the brightness of the photometric small areas S1 and S3 divided by the boundary is exactly the same, that is, if the result of e1 = e3 is obtained, it is determined that the main subject is relatively large. , Step # 205
In, both photometric small areas S1 and S3 are set as main photometric areas. In this case, EA, EB, EC are obtained by the following equations,
Finally, the photometric value is obtained by the formula.

EA13 = (e1 + e3) / 2 EB13 = (3e0 + 2 (e7 + e8) +4 (e11 +
e12)) / 15 EC13 = (3 (e2 + e4) +2 (e5 + e7 +
e8 + e10) +4 (e13 + e14) +12 (e15
+ E16 + e17 + e18)) / 70 FIG. 6 shows an example of a photographing scene of a camera in which the photometric calculation is effective. In the scene shown in this figure,
First, a focus detection area F corresponding to the center position of the face of the main subject
1 is determined by the camera focus detection area automatic selection,
The focus adjustment operation of the photographing lens 1 is performed on the focus detection area F1.

At this time, the camera performs the photometric calculation described above. That is, the luminance signals e1 and e3 of the photometric sub-regions S1 and S3 in which the focus detection region F1 is located on the division boundary are compared.

As is clear from FIG. 6, in the photometric small area S3, the bright luminance of the background is detected as the luminance of the photometric small area at the upper part, and the photometric small area S1 is
The luminance of the face of the main subject is mainly detected. For this reason, in such a backlit shooting scene, the brightness of the main subject mostly has a darker value, and as a result, the photometric small area S1 in which the darker brightness is detected is determined as the main photometric area. Therefore, by performing the photometric calculation, it is possible to obtain a photometric calculated value in which the luminance of the face of the main subject is weighted.

On the other hand, in a shooting scene having a relatively uniform luminance distribution, a photometric small area different from the photometric small area where the focus detection area corresponding to the main subject position is located on the division boundary is mainly used. Obviously, even if the photometric area is determined and the weighting operation is performed, the result is almost the same as the operation that emphasizes the main subject.

Therefore, when photographing a scene that does not have a uniform luminance distribution, as described above, if the determined focus detection area is on the dividing boundary of the plurality of photometric sub-areas, By comparing the brightness of the main photometry area and determining the photometry small area having the lowest brightness as the main photometry area, and performing the weighted photometry calculation with the maximum weight applied to the brightness of the main photometry area, It is very effective in shooting properly.

However, in a certain kind of photographing scene, it may be inappropriate to perform the photometric calculation by giving the maximum weight to the luminance signal of the photometric small area having the minimum luminance.

For example, when the main subject is wearing a black hat or wearing black clothes, if a low luminance signal is emphasized, the overall exposure may be over-appreciated. For this reason, in such a case, a luminance range higher than a luminance value lower by a predetermined step (for example, two steps) than the average value of the plurality of photometric small areas that have the determined focus detection area positioned on the boundary. A condition is added such that the photometric small area that generates the luminance signal within is considered as a candidate for the lowest luminance, but the photometric small area that generates a low luminance signal beyond a predetermined stage is excluded from the candidates. As a result, the extremely low luminance near the main subject is not weighted,
It is possible to avoid improper exposure in the scene.

(Second Embodiment) FIG. 7 shows a second embodiment of the present invention.
1 shows a viewfinder view of a single-lens reflex camera according to an embodiment. In the present embodiment, as shown in FIG. 7, the focus detection area is in addition to the nine areas (F0 to F8) of the first embodiment,
Ten areas (F9 to F18) are newly provided in the outer peripheral direction, and focus detection in a total of 19 areas is possible. Since the camera components and the operation sequence of the entire camera are the same as those of the camera of the first embodiment,
Here, only the difference in the photometric calculation will be described.

In the camera of this embodiment, the focus detection area has been expanded to 19 areas, so that the operability of the photographer in focus adjustment has been improved. However, due to the configuration of the camera, the photometric sensor is the same as in the first embodiment. A 19-split type sensor is used. Therefore, the focus detection areas F9, F10, F14, F
Reference numerals 15 are arranged on the boundaries of the four photometric sub-areas, respectively, and how the main subject is determined when the focus detection areas for performing the focus detection operation are determined to these focus detection areas F9, F10, F14, and F15. The problem is whether to perform proper photometry.

The photometric calculation method in this case will be described by taking as an example a case where the focus detection area F9 is determined as a focus detection area where the focus detection operation of the camera should be performed.

First, in the vicinity of the focus detection area F9, the focus detection area is located substantially at the center of gravity, and there are four photometric small areas S0, S1, S5, and S7 in which the main subject can be correctly measured. Therefore, the detected luminances (luminance signals) in these small photometric regions are e0, e1, e5, and e7.

At this time, as in the first embodiment, the photometric small area having the lowest luminance value among the luminance signals e0, e1, e5, and e7 is defined as a photometric small area (main photometric area) corresponding to the main subject position. ). Here, for example, the luminance signal e
When 5 is the lowest, the photometry calculation is performed with the largest weight on the photometry small area S5, and photometry with emphasis on the main subject is performed. Note that the arithmetic expression of the weighted photometric operation conforms to that described in the first embodiment.

In each of the above embodiments, the case where the focus detection area is arranged on the boundary of the plurality of photometric small areas has been described. However, in the present invention, the focus detection area is within a specific small photometric small area. The present invention can also be applied to a case where it is located at a position deviating from the position of the center of gravity and near the boundary.

Further, the present invention can be applied to various types of cameras such as a single-lens reflex camera, a lens shutter camera, a video camera, and the like. The present invention can also be applied to a device applied to an optical device or another device or an element constituting the device.

[0095]

As described above, according to the present invention,
When the focus detection area selected by the focus detection area selecting means is a focus detection area near the division boundary, the main photometry area is determined by comparing the detection luminances of a plurality of photometry areas divided by the boundary. Therefore, even if the main subject exists at a position corresponding to any one of the many focus detection areas, the focus detection area in which the focus detection operation of the main subject should be performed in viewfinder optically covers this area. Even if the photometric small area is not located almost at the center of gravity or located on the boundary, using the photometric sensor with a relatively small number of divisions, the main subject is the center and the entire object field is considered Optimum photometry can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a single-lens reflex camera according to a first embodiment of the present invention.

FIG. 2 is an electric circuit diagram of the camera.

FIG. 3 is a viewfinder view of the camera.

FIG. 4 is an operation flowchart of the camera.

FIG. 5 is a photometry calculation flowchart of the camera.

FIG. 6 is an example of a shooting composition by the camera.

FIG. 7 is a view of a viewfinder of a camera according to a second embodiment of the present invention.

[Explanation of symbols]

 1: photographing lens 6: focus detection device 6f: image sensor 7: focus plate 10: photometric sensor 11: eyepiece lens 100: CPU 102: photometric circuit 103: focus detection circuit S0 to S18: photometric small area F0 to F8, F9 to F18: focus detection area

Claims (7)

[Claims] 1. A plurality of photometric regions capable of detecting the luminance of each region are divided and formed in a shooting screen, and a plurality of focus detection regions capable of detecting a focus of each region are formed. A camera in which at least one of the plurality of focus detection areas is arranged near a division boundary of the photometry area, a focus detection area selection unit that selects an area for performing a focus detection operation from the plurality of focus detection areas, When the focus detection area selected by the focus detection area selection means is a focus detection area near the division boundary, the detection luminance of a plurality of photometry areas divided by the boundary is compared to determine a main photometry area. A camera having control means for performing the following. 2. The camera according to claim 1, wherein the vicinity of the division boundary includes a position on the division boundary. 3. The camera according to claim 1, wherein the main photometry area is an area having the lowest detection luminance among a plurality of photometry areas divided by the boundary. 4. The main photometric region is a region having the lowest detected luminance within a luminance range higher than a predetermined luminance value among a plurality of photometric regions divided by the boundary. 3. The camera according to 1 or 2. 5. The camera according to claim 1, wherein the control unit performs a photometric calculation for determining an exposure value based on the detected luminance of the main photometric region. 6. The camera according to claim 5, wherein the control unit performs a weighted photometric calculation by applying a maximum weight to the detected luminance of the main photometric region. 7. The camera according to claim 6, wherein the control unit performs the photometric calculation using only the detected luminance within a predetermined luminance range among the detected luminances of the plurality of photometric areas.