JP3131434B2 - camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a camera that evaluates a photometric value in each of a plurality of regions of a screen according to a focus state detected by a focus detection circuit in each of the regions. Things.

BACKGROUND OF THE INVENTION Conventionally, a dimmable camera that emits a flash light emitting portion toward a subject, measures light reflected from the subject, and determines the amount of light emission according to the intensity (light amount) of the reflected light. Has been released many times. Most of these cameras use a single photometric sensor to measure the light with the screen being center-weighted. Therefore, if the main subject is located at the center of the screen and has an appropriate size on the screen, it is possible to obtain an appropriate exposure amount, but the main subject may not be located at the center of the screen, or may be considerably small on the screen. In this case, the photometric sensor is greatly affected by the background, and there is a disadvantage that an appropriate exposure amount cannot be obtained.

Japanese Patent Application Laid-Open No. Sho 60-108827 proposes a multi-flash camera that divides a screen into a plurality of sections and controls the amount of light emission based on information from a plurality of photometric sensors. With this proposal, the above-mentioned drawbacks are solved.In other words, the probability of obtaining proper exposure regardless of the position and size of the main subject has been increased. Has to be set by the photographer by an external operation, and the operation is troublesome.

In view of this point, the applicant of the present application has provided, according to Japanese Patent Application No. 1-192546 or the like, distance measuring means for obtaining distance measuring information of an area corresponding to each of a plurality of photometric areas, and a focus of each area from the distance measuring means. A camera that evaluates photometric information in each of the photometric areas based on the information and controls the amount of flash light emission has been proposed.
According to this proposal, it is possible to appropriately expose the main subject automatically regardless of the position and size of the main subject in the screen, that is, without performing a troublesome operation.

However, in the proposed camera, when the mode in which the lens distance ring is not automatically driven to focus on the subject is not set, the main subject is not located in the focusing area or is out of focus. May be. Further, even in a mode in which a subject is automatically focused, there is a case where focusing cannot be performed due to a low contrast of the subject. In such a case, the position and size of the main subject in the screen cannot be determined, and the main subject cannot be properly exposed.

(Object of the Invention) It is an object of the present invention to solve the above-mentioned problems and to provide a camera capable of taking a beautiful photograph of proper exposure without failure in any scene.

(Features of the Invention) In order to achieve the above object, the present invention provides a focus detection circuit that detects a focus state or a subject distance in a plurality of areas of a screen, a photometry circuit that performs photometry in a plurality of areas of the screen, In the manual focus mode, if there is a focused area in each of the areas, a first evaluation is performed to differentiate the evaluation of the photometric value in the area corresponding to the focused area and the photometric value in another area, When all the regions are determined to be out of focus, an evaluation circuit for performing a second evaluation different from the first evaluation on the photometric value in each region is provided.

(Embodiment of the Invention) FIG. 1 is a block diagram showing an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a microcomputer for controlling the movement of each part of the camera.

Reference numeral 2 denotes a lens control circuit for controlling the distance ring of the photographing lens (not shown) and the aperture. The lens control circuit 2 performs serial communication via a data bus DBUS while receiving an LCOM signal from the microcomputer 1. A distance ring and an aperture are controlled by controlling a motor (not shown) according to the communication content.

Reference numeral 3 denotes a liquid crystal display circuit for displaying photographing information of a camera or the like, for example, a shutter speed, an aperture value, etc., in order to notify the photographer.
While receiving the COM signal, serial communication is performed via the data bus DBUS, and liquid crystal display is performed according to the communication content.

Reference numeral 4 denotes a switch sense circuit which reads the state of a switch for setting various photographing conditions by the photographer and the state of a switch indicating the state of the camera and sends the read state to the microcomputer 1.
While receiving the SWCOM signal, the data of the various switches is sent to the microcomputer 1 by serial communication via the data bus DBUS.

Reference numeral 5 denotes a strobe light emission control circuit which controls strobe light emission and light control, and receives a data bus D while receiving the STCOM signal.
Serial communication is performed with the microcomputer 1 via the BUS, and various controls are performed according to the communication contents (details will be described later).

Reference numeral 6 denotes a focus detection circuit, which is controlled by the microcomputer 1. That is, the microcomputer 1 drives the circuit 6 to determine the focus state of the subject, and drives the lens distance ring and determines whether the subject is in focus (details will be described later).

Reference numeral 7 denotes a photometric circuit which is controlled by the microcomputer 1 and performs TTL photometry of the luminance of the object scene. The photometric output obtained here is sent to the microcomputer 1 and the A / D
It is converted and used for setting exposure conditions.

Reference numeral 8 denotes a shutter control circuit that controls the travel of a first curtain and a second curtain, not shown, according to a control signal of the microcomputer 1.

Reference numeral 9 denotes a feed motor control circuit which controls a feed motor (not shown) in accordance with a control signal from the microcomputer 1 to wind and rewind the film.

10 is turned on when the front curtain of the shutter is completed, and the flash emission timing is controlled by the flash emission control circuit 5.
This is the X contact that has the function of notifying the user.

SW1 is a switch interlocked with the release button of the camera. When the microcomputer 1 recognizes that the switch SW1 is turned on, the microcomputer 1 starts an exposure operation.

FIG. 2 is a block diagram showing a configuration example of the strobe light emission control circuit 5. As shown in FIG.

In the figure, reference numeral 51 denotes a control circuit which exchanges data with the microcomputer 1 by serial communication, controls the dimming circuits 52, 53, 54 and controls the strobe 55.

Each of the dimming circuits 52 to 54 includes a logarithmic compression amplifier, a decompression transistor, an integrating capacitor, etc., starts dimming by a TTLR signal, is photoelectrically converted by a photodiode (hereinafter, referred to as a dimming sensor) PD, and receives a film. The image plane light amount of the surface is amplified by a logarithmic compression amplifier, gain is applied by an expansion transistor according to the value of the TTLG signal (light control gain information), and integration is started. When the charge of the integration capacitor exceeds a predetermined value, a CMP signal is output to the control circuit 51.

The strobe 55 is an existing one, and when the electric charge for light emission is sufficiently stored, the strobe 55 notifies the control circuit 51 of the completion of the charging by the FUL signal. When the STA signal is transmitted from the control circuit 51 receiving the signal, light emission is started, and thereafter, when the STP signal is transmitted, light emission is stopped.

FIG. 3 shows a sensitivity area of the light control sensor PD and a sensitivity area of a focus detection line sensor described later.

The light control sensors PD1 to PD3 are arranged so as to face the film surface of the camera, and have a sensitivity area with respect to the screen as shown in FIG. Further, the focus detection line sensors LS1 to LS3 described later have sensitivity areas as shown in FIG. 3 with respect to the screen by an optical system (not shown), and correspond to the sensitivity areas of the light control sensors PD1 to PD3, respectively.

FIG. 4 is a diagram showing a configuration example of the focus detection circuit 6 shown in FIG. 1, in which focus detection is performed by an existing phase difference detection method. In the figure, reference numerals 61, 62, and 63 denote focus detection units, each of which is composed of a line sensor LS1 to LS3 and a circuit for storing and reading the line sensors.

In the above configuration, the CL from the microcomputer 1
In response to the SH signal, each of the line sensors LS1 to LS3 performs photoelectric conversion and starts accumulation. Then, when the maximum of the stored charge amounts of the line sensors LS1 to LS3 reaches a predetermined amount,
The focus detection units 61 to 63 output the FB signal and stop the accumulation, and sample and hold each accumulated charge. When the microcomputer 1 detects that the FB signals have returned from all the focus detection units 61 to 63, it outputs a φ signal (clock signal), and the focus detection units 61 to 63 sequentially sample and hold according to the φ signals. The stored charge is sent to the microcomputer 1 as a DLS signal. The microcomputer 1 receiving the DLS signal performs A / D conversion on the signal, performs a predetermined operation, and performs serial communication with the lens control circuit 2 based on the operation result.

Next, a series of operations of the camera will be described with reference to the flowchart of FIG.

When the power of the camera is turned on, the microcomputer 1 communicates with the switch sense circuit 4 and reads the switches for setting each photographing condition (step 1). Next, the focus detection circuit 6 is driven to detect the focus state of each area in the screen.

Next, an area to be focused is selected, a lens is driven or not, and a reference area is selected at the time of flash dimming from a shooting mode determined by a switch or the like (step 3).

FIG. 6 shows the determination method in step 3, and its outline will be described below.

(Selection of an Area to be Focused) The determination of which area in the screen to focus the subject on includes an arbitrary selection mode that can be selected by the photographer and an automatic selection mode that can be left to the camera (FIG. 6 ( a)), the microcomputer 1 in the automatic selection mode.
Determines which area should be focused when it is determined that focusing is possible based on the focus state of each area obtained by the focus detection operation.

(With or without lens drive) In the shooting mode, the servo AF mode that repeats the focus detection operation (lens drive) until just before the release, the one-shot AF mode that holds the lens distance ring once in focus, and does not automatically drive the lens distance ring There is a manual focus mode. For example, if it is determined that focusing is possible in the out-of-focus state in the servo AF mode or one-shot AF mode, the lens drive is set to "MOVE". Is "nothing (STAY)" for lens drive.

(Selection of dimming reference area) In the servo AF mode, the selected area to be focused in both the in-focus state and the out-of-focus state is determined by the focus detection in the manual focus mode. Based on the focus state of the area, each in-focus area is set as a reference area for strobe light control. Also, servo
When focus cannot be detected in AF mode or one-shot AF mode,
Alternatively, when there is no area in the focused state in the manual focus mode or the like, all areas are equalized during flash light control.

Next, the microcomputer 1 communicates with the lens control circuit 2 when it is determined in step 3 that the lens drive is “present”, and the microcomputer 1 moves to the area to be focused selected based on the focus state of the subject. The lens distance ring is driven to focus (Steps 4 and 5). Then, the photometric circuit 7
Is operated to perform photometry for each area in the screen (step 6), and the shutter speed, aperture value, and the like are determined by calculation, and each photographing condition is displayed using the liquid crystal display circuit 3 (step 7).

If the switch SW1 has not been turned on, the microcomputer 1 repeats the operations from step 1 to step 7, and upon detecting that the switch SW1 is turned on, proceeds to the next release sequence (step 8).

When entering the release sequence, the microcomputer 1 sends dimming information based on the ISO sensitivity, focus information and the like to the control circuit 51 by communication. Then, the control circuit 51 outputs a CMP signal when the subject reflected light of the strobe light becomes appropriate, or outputs a CMP signal when the subject reflected light of the strobe light exceeds a predetermined stage. TTLG1 to TTLG3 signals are sent to the dimming circuits 52 to 54 (step 9).

Here, as shown in FIG. 7, if there is a reference area, each TTLG1 to TTLG3 signal is sent so that the area other than the reference is over a predetermined step so that the reference area is appropriate, and When there is no area, each TTLG1 to TTLG3 signal is sent so that all areas are appropriate.

Next, the microcomputer 1 includes a lens control circuit 2
The shutter control is performed by driving the shutter control circuit 8 by communicating with the camera. At this time, the control circuit 51 switches upon completion of traveling of the front curtain of the shutter.
When 10 is turned on, the STA signal is output, and flashing of the strobe 55 is started. At the same time, the control circuit 51 outputs TTLR12 to TTLR3U to start the photometric integration of the dimming circuits 52 to 54. When any one of the light control circuits 52 to 54 receives a CMP signal, it outputs an STP signal and stops the flash 55 from emitting light (step 10).

When the exposure operation is completed, the microcomputer 1
Drives the feed motor control circuit 9 to wind up the film by one frame for the next photographing (step 11).

In the above embodiment, the position and size of the main subject in the screen can be determined, and if there is a reference area, whether the strobe is appropriate The amount of light emission is controlled. Therefore, it is possible to take a photograph in which the main subject is appropriate or an object other than the main subject is not too bright.

If the position and size of the main subject in the screen cannot be determined and there is no reference area, the flash emission amount is controlled depending on which area is appropriate. Therefore, no matter where the main subject is located on the screen, an appropriate photograph can be taken as long as there is no bright object other than the other main subjects.

FIG. 8 is a block diagram showing a flash light emission control circuit according to another embodiment of the present invention, and other circuits constituting the camera are the same as those in FIG.

The strobe light emission control circuit shown in FIG. 2 in the above embodiment includes a control circuit 51, photometric sensors PD1 to PD3, a dimming circuit 52 to
54, the strobe 55, etc. are almost the same, except that a judgment circuit 56 is newly added.

The dimming circuits 52 to 54 output the LVL1 to LVL3 signals obtained by logarithmically compressing the integrated charges instead of outputting the CMP signals. Judgment circuit 56
Outputs a CMP signal to the microcomputer 51 when the value obtained by adding the LVL1 to 3 signals exceeds a predetermined value.

In this embodiment, the operations in steps 9 and 10 in the control flow of the camera shown in FIG. 5 in the above-described embodiment are changed as follows.

In the release sequence, the control circuit 51 outputs x% LVL1 to LVL3 signals of a predetermined value when the subject reflected light of the strobe light is appropriate to each of the dimming circuits 52 to 54, and reflects the subject in each area. Each TTLG1 to TTLG3 signal is sent so that the judgment circuit 56 outputs a CMP signal when the light becomes appropriate (step 9).

If there is a reference area, each TTLG1 to TTLG3 signal is sent so that "x" of the reference area is increased and "x" of the area other than the reference area is decreased. If there is no reference area, set each TTLG1 so that "x" of all areas is equal.
Send ~ TTLG3 signal.

Next, when the switch 10 (X contact) is turned on upon completion of traveling of the shutter first curtain, the control circuit 51 outputs a STA signal and causes the strobe 55 to start emitting light. At the same time, the control circuit 51
~ TTLR3 signal is output to start photometric integration of the dimming circuits 52 ~ 54. When a CMP signal comes, an STP signal is output to stop the flash 55 from emitting light (step 10).

FIGS. 9 (a) to 9 (c) are views for further detailing the embodiment.

In the example of FIG. 9 (a), 60% of "x" in the reference area,
The "x" in other areas is set to 20%. Judgment circuit 56
The conditions for outputting a CMP signal are as follows.

・ When it is appropriate in all areas …… ・ One step over (under) in the reference area, 1.5 step over (under) in other areas ……, ・ Two steps over (under) in the reference area, 3 in other areas Step over (under) ……, etc.

In other words, with respect to the reference area, even if other areas are too bright or too dark, exposures that are close to appropriate are obtained,
With respect to other areas, an exposure that is not far from the proper exposure is obtained. Therefore, it is possible to take a well-balanced photograph of the entire screen.

In the example of FIG. 9B, “x” of the reference area is 80%,
The “x” of the other areas is set to 10%, and the reference area is further weighted.

FIG. 9 (c) shows an example in which there is no reference area. The conditions under which the decision circuit 56 outputs a CMP signal are as follows.

・ When all areas are appropriate …… ・ When one area is one step lower, another area is one step over, and the remaining area is appropriate ……, ・ One area is two steps over (under) ), When each of the other areas is one step over (under),..., Etc.

That is, in any area, an exposure that is not so far from the appropriate one can be obtained, and a well-balanced photograph can be taken.

According to the present embodiment, when the position and size of the main subject can be determined, the photometric information of each area is evaluated based on the subject ranging information of each area, and the flash emission amount is controlled.
This makes it possible to take beautiful pictures with a proper exposure and a good balance between the main subject and the background.

Conventionally, in the manual focus mode, even if the main subject is not located in the distance measurement area or is out of focus, or the mode in which the subject is automatically focused, the contrast of the subject is reduced. In some cases, it may not be possible to focus due to a small amount, and in such a case, the position and size of the main subject in the screen cannot be determined, and the main subject cannot be properly exposed. In the example, when the position and size of the main subject cannot be determined, the focus information (photometric information) of each area is evaluated equally and the amount of flash light is controlled, so that the photometric information of the main subject is handled lightly. As a result, the main subject does not largely deviate from the proper one, and a photograph with almost proper exposure can be taken.

That is, in any case, it is possible to realize a camera that can obtain proper exposure and has few failures.

(Correspondence between Invention and Embodiment) In this embodiment, the dimming circuits 52 to 54 and the dimming sensor PD
1 to PD3 correspond to the photometric circuit of the present invention, and a control circuit 51 (FIG. 2);
Alternatively, the control circuit 51 and the determination circuit 56 (FIG. 8) each correspond to an evaluation circuit.

(Modification) In the present embodiment, the case where the sensitivity areas on the screen of the dimming sensor and the line sensor are as shown in FIG. 3 is assumed. However, the present invention is not limited to this and is shown in FIG. 10 (a). Such a configuration may be used. Further, as shown in FIGS. 10 (b) and 10 (c), there may be any number of sensitivity areas on the screen, and the number of sensitivity areas on the screen of the dimming sensor and the line sensor does not need to match.

Further, as a means (focus detection circuit) for obtaining distance measurement information, a phase difference detection method is assumed, but any existing method can be used. For example, when the distance measurement method is a method of calculating an absolute distance, when the position of the lens distance ring and the absolute distance of the subject match each other, the focus state is set. What is necessary is just to obtain the focus information of the subject.

(Effects of the Invention) As described above, according to the present invention, it is possible to take a beautiful photograph with proper exposure without any failure in any scene.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration example of a strobe light emission control circuit shown in FIG. 1, and FIG. 3 is a light control sensor and a line sensor in this embodiment, respectively. FIG. 4 is a block diagram showing a configuration example of a focus detection circuit shown in FIG. 1, FIG. 5 is a flowchart showing a series of operations in one embodiment of the present invention, and FIG. 6 (a). (B) is a diagram showing a determination method in step 3 shown in FIG. 5, FIG. 7 is a diagram showing a dimming value setting method in step 9 shown in FIG. 5, and FIG. 8 is another embodiment of the present invention. 9 (a), 9 (b), and 9 (c) show a change in image plane light amount in each zone by weighting of a dimming gain in another embodiment of the present invention. Figures 10 (a), (b) and (c) show the light control sensor and the line sensor. It is a diagram showing another example of each of the sensitivity area. DESCRIPTION OF SYMBOLS 1 ... microcomputer, 5 ... strobe light emission control circuit, 6 ... focus detection circuit, 7 ... photometric circuit, 51 ... control circuit, 52-54 ... dimming circuit, 56 ... determination circuit, 57 ... …
Level detection circuit, PD1 to PD3 ... Dimming sensor.

Claims (3)

(57) [Claims] A focus detection circuit for detecting a focus state or a subject distance in each of a plurality of areas of the screen; a photometric circuit for measuring light in each of a plurality of areas of the screen; If there is a region, a first evaluation is performed to make the photometric value in the region corresponding to the in-focus region different from the photometric value in the other region, and all of the respective regions are determined to be out of focus. A camera provided with an evaluation circuit for performing a second evaluation different from the first evaluation on the photometric value in each of the areas. 2. The method according to claim 1, wherein the second evaluation is to uniformly evaluate a photometric value in each of the areas.
The described camera. 3. The camera according to claim 1, further comprising a light emission amount control circuit for adjusting a flash light emission amount based on an evaluation result of the evaluation circuit.