JP2778000B2 - Flash photography system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention is provided with photometric means for measuring the reflected light of a flash projected on an object in a plurality of areas, and the flash is provided in accordance with the output of the photometric means. The present invention relates to an improvement in a flash photographing system for controlling a light emission amount.

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.

However, since most of the systems use a single photometric sensor to measure the light with the screen center-weighted and adjust the light,
If the main subject is located at the center of the screen and has an appropriate size, it is possible to obtain an appropriate exposure amount, but if the main subject is not located at the center of the screen or is small with respect to the screen. In addition, there has been a problem that an appropriate exposure amount cannot be obtained due to the influence of the background light amount.

In view of this point, Japanese Patent Laying-Open No. 60-108827 proposes a multi-flash camera in which a plurality of photometric sensors are arranged and each of them is variably controlled to determine (control) a light emission amount. The photographer had to set which part of the photometry should be emphasized by an external operation, and the operation was troublesome.

In Japanese Patent Application Laid-Open No. 56-135823, a plurality of areas on a screen are measured with and without a flash, respectively, and the measured values are compared to obtain an image of an object located closest to the camera. The area where the image is located is selected, and the light emission amount is controlled by the photometric value of the area. In this method, the closest subject has an appropriate exposure, but if the main subject is not located closest, the main subject will not have an appropriate exposure and the balance with the background will be considered. Had not been. In addition, there is a problem in that flashing must be performed once before photographing, and power consumption is drastic.

Also, in U.S. Pat. No. 4,794,043, a method has been proposed in which a plurality of areas of a screen are measured for light and exposure is performed based on a photometric value of an area corresponding to a ranging area. There is no mention of photometric evaluation of. The photometric evaluation of a subject illuminated by flash light emission differs greatly depending on the distance of the subject from the flash light emitting unit, the time of flash light emission, and the like, and is different from the photometry of stationary light.

(Purpose of the Invention) An object of the present invention is to solve the above-mentioned problems and to perform flash photography in which a main subject can be properly exposed and a photograph taken with a good balance with the background can be taken without troublesome operation. Is to provide a system.

(Features of the Invention) In order to achieve the above object, the present invention comprises a photometric unit for measuring the reflected light of a flash projected on an object in a plurality of regions, and a flash is provided in accordance with an output of the photometric unit. In a flash photographing system for controlling a light emission amount, focus detection means for detecting a focus state or a state related to a distance in each of the plurality of areas, and a focus state or a state related to a distance in each area detected by the focus detection means. Evaluation means for weighting the photometric output in each area measured by the photometric means, and control means for controlling the amount of emitted light based on the photometric output weighted by the evaluation means.

Further, the present invention includes a photometric unit for measuring the reflected light of the flash light projected on the object in a plurality of regions,
In a flash photographing system for controlling a flash light emission amount according to an integrated value of an output of a photometric unit, a focus detecting unit that detects a focus state or a state related to a distance in each of the plurality of areas, and the focus detecting unit detects the focus state or a state related to a distance. Evaluation means for weighting an integrated value of photometric output in each area measured by the photometric means according to a focus state or a state relating to a distance of each area; and an integrated value of photometric output weighted by the evaluation means Control means for controlling the amount of emitted light based on the

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the figure, reference numeral 1 denotes a microcomputer for controlling the movement of each part of the camera, and 2 denotes a lens control circuit for driving and controlling a focus adjustment motor and an aperture blade control motor for a taking lens (not shown). 2 performs serial communication via the data bus DBUS while receiving the LCOM signal from the microcomputer 1, and when motor drive information is received by serial communication, drives the motor (not shown) based on the information. At the same time, the lens control circuit 2 sends various kinds of lens information to the microcomputer 1 by serial communication.

Reference numeral 3 denotes information of each photographing of the camera, for example, shutter speed,
A liquid crystal display circuit for driving a liquid crystal display (not shown) for notifying a photographer of an aperture value and the like. The data bus D receives a DPCOM signal from the microcomputer 1.
Serial communication is performed via the BUS, and when display data is received by the serial communication, the liquid crystal display is driven according to the display data.

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 dimming control circuit for controlling the strobe light emission and the light emission stop function by TTL light control, and performs serial communication with the microcomputer 1 via the data bus DBUS while receiving the STCOM signal to control the strobe light control. Various controls are performed by receiving data.

Reference numeral 6 denotes a focus detection circuit in which a line sensor for performing AF by an existing phase difference detection method and a circuit for storing and reading out the data are formed as a unit.

Reference numeral 7 denotes a photometric circuit which is controlled by the microcomputer 1 and performs photometry of an object scene. The photometric output obtained here is sent to the microcomputer 1 and A / D converted to be 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.

A feeding circuit 9 controls a feeding motor (not shown) in accordance with a control signal from the microcomputer 1 to wind and rewind the film.

Reference numeral 10 denotes an X contact which is turned on at the timing when the front curtain of the shutter has completed traveling and notifies the flash emission dimming control circuit 5 of the flash emission timing.

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 surface light amount of the surface is amplified by a logarithmic compression amplifier, gained by an expansion transistor according to the value of the TTLG signal (dimming gain information), and integrated by an integration capacitor. When the charge of the integration capacitor exceeds a predetermined value, the control circuit 51
Outputs CMP signal.

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 charging by the FVL signal. When the STA signal is transmitted from the control circuit 51 receiving the signal, the light emission is started, and thereafter, when the SPT signal is transmitted, the 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 an example of the configuration of a focus detection circuit 6 shown in FIG. 1. In FIG. 4, reference numerals 61, 62, and 63 denote focus detection units, respectively, and line sensors LS1 to LS3 and a circuit for storing and reading the same. It is composed of

Next, the camera operation after the focus detection operation will be described with reference to FIG.

In response to the CLSH signal from the microcomputer 1, the line sensors LS1 to LS3 respectively perform photoelectric conversion and start accumulation.
When the largest one of the accumulated charge amounts of the line sensors LS1 to LS3 reaches a predetermined amount, the focus detection unit
61 to 63 output the FB signal and stop the accumulation, 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, the microcomputer 1 outputs a φ signal (clock signal),
The focus detection units 61 to 63 send the accumulated charges sequentially sampled and held in accordance with the φ signal to the microcomputer 1 as DLS signals. 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. The lens control circuit 2 drives the focus adjustment motor based on the transmitted data. At this time, various proposals have been made as to which of the sensitivity areas of the line sensors LS1 to LS3 on the screen should be focused. For example, focusing on the closest object, or focusing so that all areas are within the depth of field.

When the AF operation as described above is completed, the microcomputer 1 sends information such as which zone is in focus and which zone is within the depth of field to the flash emission dimming control circuit 5. Then, the control circuit 51 in the circuit 5 sends the dimming gain information (TTLG signal) to the dimming circuits 51 to 53 based on the sent respective focusing information. Then, X contact
When 10 is turned on, the control circuit 51 uses the STA signal to
The light emission of 5 is started, and at the same time, the light control is started by the TTLR signal. Then, from the dimming circuits 52 to 54, the CMP associated with the end of dimming
When the signal is sent, the emission of the strobe 55 is stopped by the STP signal.

Relationship between focusing and non-focusing of each zone and dimming gain,
FIG. 5 shows the relationship between the CMP signal and the STP signal.

The control method shown in FIG. 5 is merely an example, and the setting of the dimming gain can be selected indefinitely depending on each focusing condition, such as “appropriate”, “under a predetermined step”, and “over a predetermined step”. In addition, the light emission stop control can select not only “OR (logical sum)” but also “AND (logical product)” (output an STP signal when all the signals of CMP1 to CMP3 are received). Further, when the light control correction is applied, the light control gain may be corrected for both the in-focus zone and the out-of-focus zone,
Light adjustment gain correction may be applied only to the focusing zone.

FIG. 6 is a flowchart showing an outline of a flow of a series of operations of the camera. When the release button (not shown) is not pressed, the switch SW1 is OFF, so that the switch sensing (step 1) and the photometry (step 2) are performed. ) And display (step 3) are repeated. When the release button is pressed and switch SW1 is turned on, step 4 to step 5
To perform AF operations such as reading out of the focus detection sensor, calculation, and driving of a lens focus adjustment motor. In the next step 6, a strobe light control gain is set based on the focusing information obtained in step 5, and the apparatus enters a light control preparation state. Further, in the next step 7, control is performed such that the shutter is exposed for a predetermined time (at this time, the operation of flash emission and stop is performed simultaneously). When the release is completed, in step S8, the film for one screen is fed for the next photographing.

FIG. 7 is a block diagram showing a flash light emission dimming 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 dimming control circuit shown in FIG. 2 in the embodiment is a control circuit 51, photometric sensors PD1 to PD3, a dimming circuit.
52 to 54, the strobe 55, and the like are almost the same, except that an addition circuit 56 and a level detection circuit 57 are newly added.

The dimming circuits 52 to 54 output the LVL1 to 3 signals which are values integrated into the integrating capacitors without outputting the CMP signal. The addition circuit 56 is a value obtained by logarithmically converting the LVL1 to LVL3 signals and adding them.
Outputs ADL signal. When the ADL signal exceeds a predetermined value, the level detection circuit 56 outputs a CMP signal. The operation of the control circuit 51 is the same as that of the above embodiment, and the dimming gain information (TTLG
Signal), the start of light emission of the strobe 55, the start of the dimming operation, and the operation of stopping the light emission of the strobe 55 in response to the input of the CMP signal.

The dimming gain is set so that a CMP signal is output when an arbitrary image surface light quantity is obtained in each zone.

Further, even with the same image plane light amount, the balance of each zone changes by changing the weighting of the light control gain in each zone. This will be described with reference to FIG.

In the example of FIG. 8 (a), the LV when each zone is properly exposed.
Dimming gain information (TTLG signal) is set so that the value obtained by logarithmically converting the L signal becomes "3: 1: 1". When the zone of the weighted light control sensor PD1 is over by one step, when the zones of the photometric sensors PD2 and PD3 are each under -1.5 step, a CMP signal is output. In other words, the weighted zones are not too affected if the other zones are too bright or too dark, so that exposures close to the appropriate level can be obtained. Since an exposure amount that is not so far can be obtained, a balanced exposure amount can be obtained for the entire screen.

 The same applies to the example of FIG. 8 (b).

In the other embodiment, the weighting of the dimming gain is changed according to the focusing / non-focusing information of each zone. That is, by adding weights to the in-focus zone and the zone within the depth of field as shown in FIG. 9, it is possible to take a well-balanced strobe photograph with proper exposure for the main subject (the subject to be focused).

In this embodiment, photometry is performed at the same time as photometry in a plurality of areas in the screen, and a photometric value is evaluated based on focus information (focusing / non-focusing information) of each area to control the light emission amount. In order to predict the position and size of the main subject in the screen to some extent, it is possible to control the main subject to obtain an appropriate exposure, and to achieve a proper exposure amount with a good balance with the background. Thus, it is possible to realize a multi-flash camera capable of controlling the amount of flash light emission.

(Correspondence between Invention and Embodiment) In the present embodiment, the dimming circuits 52 to 54 and the photometric sensor PD
1 to PD3 correspond to the photometric means of the present invention, and the focus detection circuit 6 corresponds to the focus detection means of the present invention.
1, the control circuit 51, the addition circuit 56, and the level detection circuit 57 correspond to the evaluation means and the control means of the present invention.

(Effects of the Invention) As described above, according to the present invention, it is possible to perform flash photography in which a main subject is properly exposed and a balance with the background is obtained without performing a troublesome operation.

[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 dimming control circuit shown in FIG. 1, and FIG. 3 is sensitivity of a dimming sensor in the present embodiment. FIG. 4 is a block diagram showing a configuration example of a focus detection circuit shown in FIG. 1; FIG. 5 is a block diagram showing a configuration example of a focus detection circuit; FIG. FIG. 6 is a flow chart showing a series of operations in one embodiment of the present invention; FIG. 7 is a flowchart showing a series of operations in one embodiment of the present invention; FIG. 8 is a block diagram showing a configuration example, FIG. 8 is a diagram showing a change in the image surface light amount of each zone by weighting the dimming gain in another embodiment of the present invention, and FIG. 9 is also a diagram in another embodiment of the present invention. The relationship between focus state and dimming gain It is to figure. 6: Focus detection circuit, 5: Flash emission dimming control circuit, 51: Control circuit, 52 to 54: Dimming circuit, 56: Addition circuit, 57: Level detection circuit, PD1 to PD3 ... Photometric sensor.

Claims (3)

(57) [Claims] 1. A flash photographing system, comprising: a photometer for measuring the reflected light of a flash projected on an object in a plurality of areas, and controlling a flash emission amount according to an output of the photometer. Focus detection means for detecting a focus state or a state related to a distance in each area, and each area measured by the photometer means according to a focus state or a state related to a distance of each area detected by the focus detection means. A flash photographing system, comprising: an evaluation unit that weights the photometric output of the image forming apparatus; and a control unit that controls the amount of emitted light based on the photometric output weighted by the evaluation unit. 2. The method according to claim 1, wherein the weighting of the photometric output from a region whose focus state is within a predetermined defocus amount is different from the weighting of the photometric output from other regions. The flash photography system according to 1. 3. A flash photographing system comprising photometric means for measuring the reflected light of a flash projected on an object in a plurality of areas, and controlling the amount of flash light emission in accordance with the integrated value of the output of the photometric means. Focus detection means for respectively detecting a focus state or a distance-related state in the plurality of areas; and photometry performed by the photometric means in accordance with a focus state or a distance-related state of each area detected by the focus detection means A flash unit comprising: an evaluation unit that weights an integral value of a photometric output in each region; and a control unit that controls light emission amount based on the integral value of the photometric output weighted by the evaluation unit. Shooting system.