JPS63115148A - Photometry controller for flash light quantity - Google Patents

Abstract

PURPOSE:To obtain proper exposure by dividing and irradiating an object by plural flash light emission tubes which have different irradiation ranges and detecting reflected light beams from respective areas. CONSTITUTION:Panels 3-6 have flash tubes internally and an image plane Y is divided into four areas 100a-100d and radiated. The respective areas are wider in outward directions than the image plane Y, the areas 100a and 100c have their radiation angles overlapping each other at a part where oblique lines cross one another, and the respective areas have radiation angles overlapping partially with one another. Then 10-13 are photodetectors which receive reflected light beams from light measurement zones 105a-105d and 14 is a photodetector for reflected light from the zone 105e of the center part. The light receiving signals of the respective elements 10-13 are integrated independently of one another and when an integral value reaches a specific value, a light emission stop signal is supplied to a corresponding flash tube. Consequently, light is distributed properly to all the areas and proper exposure is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a flashlight emitting device for a camera, and in particular, a flashlight emitting device for a camera, in particular, a subject is irradiated in sections with a plurality of flashlight emitting tubes each having a different irradiation range, and each divided area is The present invention relates to a flash amount metering control device for a flash light emitting device for a camera, which controls the amount of light emitted from each region and provides appropriate exposure over the entire screen.

<Prior art> Conventionally, when performing strobe flash photography in a relatively dark place such as indoors, when there are two subjects at a relatively close position and a relatively far position from the strobe S as shown in Figure 1, the front subject If you shoot to give A the proper amount of light, object B in the background will appear.
The amount of light will be insufficient, and the image B' of subject B will be dark and difficult to see as shown in Figure 2.Conversely, if you shoot to give the proper amount of light to subject B in the background, the subject in the foreground will have insufficient light. As a result, as shown in Fig. 3, the image A' of subject A becomes completely white, and the facial expressions become blurred (the image disappears).

The cause will be explained using FIG. 4. Figure 4 shows camera C
FIG. 3 is a view of a strobe S and subjects A and B attached to an accessory shoe, viewed from above.

Ll is the distance from the strobe S to the subject A in the foreground, L2
is the distance from the strobe S to the object B at the back. O is the irradiation angle of the flash light of the strobe S, which is equal to or larger than the angle of view of the camera C.

When the aperture value of the lens of camera C is F and the distance from strobe C to the subject is L, the guide number GN is GN=FXL. Here, set the guide number GN of the strobe S to 22.
(F-m), L 1 = 2m, L 2 = 5.
When the distance is 5 m, the aperture value F1 that gives proper exposure to the subject in the foreground is F=11, and the aperture value that gives proper exposure to the subject in the back is F=4. However, since Strobe S provides the same amount of light over the entire 0 coverage angle, if you set the aperture to properly expose subject A in the foreground,
Subject B in the background is underexposed by three steps, resulting in a photo like the one shown in Figure 2. Furthermore, if the aperture is set so that subject B in the background is properly exposed, subject A in the foreground will be overexposed by three steps, resulting in a photograph as shown in Figure 3.

Also, instead of emitting the full amount of light during flash photography and changing the aperture depending on the distance, the light emitted from the strobe's light emitting part hits the subject, and the reflected light is received by the strobe or camera's light receiving part. The amount of light received is integrated, and when the reflected light reaches a certain value, a control circuit generates a signal, activates a flash stop circuit, and stops flashing to obtain the correct exposure. Even when using this, both subjects A and B will not be properly exposed; for example, if subject A is 1.5 stops over, subject B will be 1.5 stops underexposed. As a method for solving this problem, a device disclosed in Japanese Patent Laid-Open No. 47-27524 has been proposed.

The nuclear device is equipped with four flash tubes having irradiation angles that divide the imaging screen Y into four partially overlapping areas 100a-100d, as shown in Figure 5, to irradiate each divided area. The reflected light from the divided areas is received independently, and when the amount of light received in each area reaches a predetermined value, the light emission of the individual flash tubes for each area is stopped. Each is controlled to achieve appropriate exposure.

However, in the conventional device, when flash control is performed, the following problem occurs when, for example, the subject 0 is present only in the center of the screen as shown in FIG.

If the subject exists only in the center, the proportion of the subject in each area will be low, and the light control level for each area is set to give the appropriate exposure for each area as a whole.
As a result, the main subject 0 tends to be overexposed. This is quite a problem considering that the subject is usually framed and photographed in the center of the screen.

Purpose The present invention has been made in view of the above-mentioned matters.The screen is divided, a flash is emitted to each divided area, the reflected light of each divided area is measured by a light receiving element, and each A light-receiving element is installed to control the amount of flash light in each divided area and measure the light in the center of the screen, and when the amount of light received by the light-receiving element reaches a predetermined value, the flash is forcibly stopped in the entire area. It is an object of the present invention to provide a flash amount photometry control device that solves the above-mentioned problems.

<Embodiment> FIG. 6 is an external view showing an embodiment of a flash device employing the photometry control device according to the present invention. In the figure, 3 to 6 each have a flash tube inside, and as shown in FIG. This is a panel for dividing the screen Y into four areas 100a to 1OOd and irradiating them. Each area is wide outwardly with respect to the screen Y, and the irradiation angle is set such that each area partially overlaps with the other. For example, as shown in FIG. 7, the areas 100a and 100c have irradiation angles that overlap each other at the area where the diagonal lines intersect. 10 to 13 are light receiving elements that receive reflected light from the photometric zones 105a to 105d in each of the above regions, and 14 is a light receiving element that receives reflected light from the zone 105e at the center of the screen.

FIG. 8 is a circuit diagram showing an example of the circuit of the strobe device shown in FIG.
Each discharge tube 3', 4', 5', 6 in 6
' shows a light amount control circuit including a trigger circuit for emitting light. In addition, the block diagrams ■, ■, ■, and ■ represent the integrated values obtained by independently integrating the light reception signals of the light receiving elements 10-13 provided for each of the zones 105a, 105b, 105c, and 105d in FIG. When the light amount control circuit blocks n, m, rv reach a predetermined value, the light amount control circuit blocks n, m, rv.

2 shows a dimming circuit for giving a light emission stop signal to the discharge tube. Block X is the photometric zone l 0 shown in FIG.
This is a dimming circuit block that integrates the light reception signal of the light receiving element 14 that receives light from the light receiving element 5e. Block I indicates a DC-DC converter circuit for supplying luminous energy to each flash tube, and 7 indicates a rectifying element which together with a capacitor 8 constitutes a power supply circuit for supplying power to each dimming circuit. 9 indicates a switch for causing each flash tube to emit light.

FIG. 9 is a circuit diagram showing an embodiment of blocks n, m, rv, and v. 17 in the figure is the DC-DC converter circuit I
The main capacitor 23 is charged via the diode 16, the trigger capacitor 23 is charged via the resistor 18, and the thyristor 22 is connected in parallel to the capacitor 23 and the primary coil of the trigger transformer 23. The gate of the thyristor is connected to switch 9. A thyristor 26 is connected in parallel to the flash tube and is turned on in response to a signal input to a terminal to stop the flash tube from emitting light.

FIG. 1O is a circuit diagram showing an example of a dimming circuit.

Since the dimming circuits ■, ■, ■, and ■ are equivalent, only the ■ block and the X block are shown. Terminal 43.44
are power supply terminals, and capacitor 8 shown in FIG.
Connected to the positive and negative sides of the 45 is a control terminal to which a low level voltage is applied for a certain period of time in synchronization with the start of light emission of the flash tube by a control circuit (not shown); 13 is a sixth control terminal;
The photodetector shown in the figure measures the photometry zone 105d within the zone 100d illuminated by the flash tube 6' shown in FIG. 30
is a switch element 31 that turns off in response to a low level;
32 is an integrating capacitor, 32 is a resistor, and 33 is a variable resistor, which is set to a predetermined value based on information such as film sensitivity and lens FNo. The output of a comparator 34 that compares the divided voltage of the resistor 32 and variable resistor 33 with the voltage of the integrating capacitor 31 is input to the gate of an OR circuit 36. The resistor 35 is a pull-up resistor for the comparator 34. The input of the OR circuit 36 is connected to the light emission stop signal line d of the block X having the same configuration.

Since the block
Integration operation is performed by the capacitor 38 for the output of 4. Another block ■.

■, ■The configuration is also the same as block ■, and each light receiving element 10
12 are integrated, and the output of the comparator 41 of block X is input, and the OR signal of the output of the comparator 41 and the output of the comparator in each block is output to each terminal b1 to b3.

Next, the operation of the present invention with the above configuration will be explained.

The strobe device shown in FIG. 6 is attached to the camera, and the power switch 2 (FIG. 8) of the strobe device is turned on.

As a result, the main capacitor 17 and trigger capacitor 23 of each block n, m, mV, and V are charged with the output from the DC-DC converter I. The capacitor 8 is also charged, and an operating voltage is applied to the dimming circuits of blocks 1 to X. In this state, when the camera is released and the front curtain of the shutter moves, the switch 9 is closed in synchronization with the movement of the shutter, and the light emission start signal is sent to the signal line a1. Each block ■ ~ V via a2゜a3+ a4
and thyristor 2 for trigger activation of each block.
2, the trigger thyristor is turned on.

Therefore, the previously charged trigger capacitor 23 in each block is discharged via the trigger coil to provide a high voltage trigger output to the flash tube. For this reason, flash tube 3/,
4/, /, and s/ emit light. The light intensity of these flash tubes is as shown in Figure 7 (100aS100
b, 1ooc.

Each zone of 100d is irradiated. Furthermore, the reflected light from these zones is 105a and 105 shown in FIG.
b.

A light receiving element 10 that measures light in the range of 105c and 105d
．． The light is received at 11°12.13.

In addition, along with the flash light emission, a low level signal is sent to each dimming circuit■
Since the voltage is applied to the terminal 45 of ~X, the switches shorting the capacitors of each block are turned off, and the capacitors are charged with the output of each light receiving element. In this way, each block ■ to ■ performs an integral operation on the reflected light from each photometric zone 105a to 105d, and when the integral value reaches a predetermined value, the dimmer circuit whose integral value has reached the predetermined value A high level is sent from the comparator and the corresponding flash tube stops emitting light. The above operations are performed for each block, and the amount of light emitted is controlled for each photometric zone, so that appropriate exposure is always performed regardless of the condition of the subject.

Each photometry zone 105a to 1 by each of the above-mentioned light control circuits ■ to ■
While photometry and integration of photometric values for 05d are performed, a low level signal is also applied to the switch 37 of the dimming circuit Therefore, the output of the light receiving element 14 is also integrated by the integrating circuit 38. Since the light receiving element 14 receives the reflected light from the central zone 105e, the integrating operation for the reflected light from the central zone is performed. is performed in the circuit X.

Now, if the subject is located only in the center of the screen Y as shown in FIG. 5, the reflected light from the central photometric zone 105e will be larger than the reflected light from other zones. Therefore, in this case, the output of the light receiving element 14 that receives the reflected light from the central photometry zone 105e is adjusted before the integral value of each of the dimming circuits ■ to ■ that integrates the reflected light for the zones 105a to 105d reaches a predetermined value. When the integrated value of the integrating capacitor 38 reaches a predetermined value, the comparator 41 outputs a high level. The output of the comparator 41 of the dimming circuit Even if each integral value in the dimming circuits ■~■ does not reach the predetermined value, a high level as a light emission stop signal is sent to the terminals -b4 of each of the dimming circuits ■~■, and each block ■~V. The thyristor 26 is turned on to stop the flash tubes 3' to 6' from emitting light. Therefore, even if the subject exists only in the center of the screen, proper exposure can be achieved.

Effect> As explained above, in the present invention, the photographing screen is divided into a plurality of parts, and the flash light emitting device is adapted to illuminate each divided part, and the light receiving area is set approximately at the center of each divided part as the photometric zone. A central light-receiving sensor that has a sensor and a metering zone approximately at the center of the photographic screen is arranged, and the sensors of each divided section and the central sensor are connected at the OR, respectively.
Since the amount of light emitted by the flash light emitting device of each divided section is controlled by a signal from one of the two parties, even if there are multiple subjects at different distances on the screen, the appropriate light distribution for each subject can be achieved. In addition, appropriate light distribution can be achieved even when a subject exists only in the center.

In the embodiment, four strobe flash tubes are used, but the present invention may be applied to a two-light flash tube that divides the right side and left side of the screen.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram when taking pictures using a conventional single-lamp type flash device, and Figures 2 and 3 show the exposure conditions when taking pictures using a conventional single-lamp type flash device. An explanatory diagram, FIG. 4 is an explanatory diagram illustrating the exposure conditions for a subject in photography using a conventional single-flash type flash device, and FIG. 5 is an explanatory diagram illustrating the operation of a conventional multiple-flash type flash device.
FIG. 6 is an external view showing the external appearance of a flash device employing the photometry control device according to the present invention, FIG. 7 is an explanatory diagram showing the photometry state of the flash device shown in FIG. 6, and FIG. 8 is a view of the flash device shown in FIG. 6. A circuit diagram showing the circuit of the device, FIG. 9 is a circuit diagram showing the configuration of blocks ■ to V shown in FIG. 8, and FIG. 10 is a circuit diagram showing the configuration of blocks IX shown in FIG. 8.
, is a circuit diagram showing the configuration of X. 10 to 14... Light receiving element, 3' to 6'... Flash tube, ■ to X... Dimming circuit.

Claims (1)

[Claims] The photographic screen is divided into a plurality of parts, and a plurality of flash means are provided to independently irradiate each divided region with flash light, and each divided region is provided corresponding to each divided region to independently receive reflected light from each divided region. a plurality of light receiving elements, and a first control circuit that stops the flashing of the flashing means for irradiating the divided area corresponding to each light receiving element when the amount of light received by each light receiving element reaches a predetermined value. A central light-receiving element that controls the amount of flash light for each divided area and receives reflected light from the central area of the photographic screen, and when the amount of light received by the central light-receiving element reaches a predetermined value, it corresponds to each of the divided areas. a second device for simultaneously stopping the flashing of the plurality of flashing means independently of the amount of light received by the light receiving element;
1. A flash amount photometry control device, comprising: a control circuit.