JPH05127232A - Flashmatic camera - Google Patents

Abstract

PURPOSE:To provide a flashmatic camera capable of flash-photographing all objects positioned at different ranges with an apprepriate exposure. CONSTITUTION:The flashmatic camera which executes the flash photographing by calculating a stop value for obtaining the apprepriate exposure based on the guide number of a flashing device and the range of the reference object and setting a stop to the calculated stop value is provided with light quantity adjustment means 16a-16c consisting of plural members whose transmissivity can be varied and independently adjust the illuminating light quantity of plural illuminating areas within the object by transmitting the illimunating light of the flashing device and guiding it to a field, a multiple range-finding means 24 independently executing the range-finding of the objects respectively positioning in the plural illuminating areas and transmissivity control means 21 and 22 which control the transmissivity of the respective adjustment means 16a-16c based on the range of the reference object and the respective range- finding outputs of the range-finding means 24 before the flash photographing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera for flash photography by a flashmatic system.

[0002]

2. Description of the Related Art The flashmatic system is one in which an electronic flash device is caused to emit light at a constant light emission amount and the aperture value is controlled to adjust the light amount guided to the film surface to obtain proper exposure. That is, in a flashmatic camera, an aperture value is calculated from a guide number of an electronic flash device, a reference subject distance (for example, shooting distance), and film sensitivity by a predetermined calculation formula, and the aperture is set to the calculated aperture value. The electronic flash device is fully illuminated to take a picture. As a result, the subject located at the reference subject distance is photographed with proper exposure.

[0003]

However, in such a system, since the amount of light guided to each part of the object field is the same, all the subjects can be properly exposed when a plurality of subjects exist at different distances. Flash photography is not possible. That is, although proper exposure can be obtained for a subject located at the reference subject distance, a subject located at a shorter distance than this is overexposed and a subject located at a longer distance is underexposed.

An object of the present invention is to provide a flashmatic camera capable of taking flash images of all subjects located at different distances with proper exposure.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an aperture value for obtaining a proper exposure is calculated from a guide number of a flash device and a reference subject distance, and the aperture is set to the calculated aperture value for flash photography. Applies to flashmatic cameras that do. Then, the light amount is made up of a plurality of members having variable light transmittances, and the illumination light amount of each of the plurality of illumination regions in the object field is independently adjusted by transmitting the illumination light of the flash device to the object field. Adjusting means, multi-distance measuring means for independently measuring distances to objects located respectively in a plurality of illumination areas, and prior to flash photography, each light quantity based on the reference object distance and each distance-measuring output of the multi-distance measuring means. And a transmittance control means for controlling the transmittance of the adjusting means, thereby solving the above problems.

[0006]

The multi-distance measuring means independently measures the distance to the subject located in each illumination area. The transmissivity control means controls the transmissivity of each light amount adjusting means based on the reference object distance used for the aperture value calculation and each distance measurement output of the multi distance measuring means before the flash photography. When flash photography is performed in this state, the illumination light of the flash device passes through the light amount adjusting means (the transmittance of which is controlled) and illuminates each illumination area of the object scene. At this time, since the illumination light amount of each illumination area is adjusted according to the transmittance of the light amount adjusting means, it becomes possible to perform flash photography with proper exposure for all subjects located at different distances.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a perspective view of the flashmatic camera according to the present invention viewed from the front. On the front of the camera body 11,
A lens barrel 13 having a taking lens 12 is provided, a viewfinder objective lens 14, distance measuring windows 15a and 15b for active autofocus, and a light emitting window 16 of an electronic flash device are provided. Also, the camera body 11
A release button 17, a liquid crystal display device 18, and a light emission mode switching button 19 are provided on the upper surface of the.

The electronic flash device of the present embodiment has three light emitting portions (not shown) arranged side by side in the lateral direction of the camera, and the guide numbers of the respective light emitting portions are equal and constant. The light emitting window 16
Is divided into three regions 16a to 16c respectively located on the front surfaces of these three light emitting portions, each of which is composed of an electrochromic element (hereinafter, an EC element). The light emitted from each light emitting unit is the EC elements 16a to 16c.
And the left region 50 of the field 50 shown in FIG.
a, the central area 50b, and the right area 50c are illuminated. The EC elements 16a to 16c are blackened when a voltage is applied, and the degree of blackening varies depending on the applied voltage. The higher the degree of blackening, the lower the transmittance of the irradiation light. FIG. 4 shows the relationship between the applied voltage to the EC elements 16a to 16c and the transmissivity thereof. As can be seen from this figure, the transmissivity is 100% when the applied voltage is zero, and the higher the applied voltage, the blacker the image becomes. The degree of conversion becomes higher and the transmittance decreases.

FIG. 1 is a block diagram of a control system of the camera. The control circuit 21 including a CPU, ROM, RAM, etc. includes an EC drive circuit 22 for applying a voltage to the EC elements 16a to 16c to drive it, a light emission control circuit 23 for an electronic flash device, and an active autofocus. Type distance measuring circuit 24, film information detection circuit 25, exposure control circuit 26
Are connected. The distance measuring circuit 24 includes three sets of distance measuring units 30 each including a light emitting unit 31 and a light receiving unit 32 as shown in FIG.
(Only one set is shown) are connected. Infrared light is emitted in a beam form from each light projecting unit 31, and the distance measuring area 51 in FIG.
objects O1, 02, O existing in a, 51b, 51c
The reflected light from 3 is received by each light receiving element 32, and the distances (object distances) D1, D2, D3 from the objects O1 to O3 are respectively detected by the light receiving positions. here,
The distance measuring areas 51a to 51c are provided in the illumination areas 50a to 50c of the electronic flash device, respectively.

The film information detecting circuit 25 reads the film sensitivity and the number of photographed images from the DX code provided on the film cartridge and inputs them to the control circuit 21. Further, the exposure control circuit 26 responds to a command from the control circuit 21 to drive an aperture or a shutter (not shown) to perform photographing.

The control circuit 21 also includes the release button 1 described above.
Half-push switch SW1 which is turned on by half-push operation of 7, and full-push switch S which is turned on by full-push operation of release button 17.
W2 and a light emission mode selection switch SW3 that is turned on and off each time the light emission mode selection button 19 is operated are connected. In the present embodiment, it is assumed that when the switch SW3 is turned on, a light emission mode in which flash light emission is performed is set, and when the switch SW3 is turned off, a light emission prohibition mode in which flash light emission is not performed is set.

Next, the control procedure of the flash photographing operation by the control circuit 21 will be described with reference to the flowchart of FIG. This program is started when the half-push switch SW1 is turned on. First, in step S1, the light emission mode switch S
Whether or not flash photography is performed is determined by the on / off state of W3. If it is not flash photography, AE photography without using the electronic flash device is performed in step S12 (detailed description is omitted), and if it is flash photography, the process proceeds to step S2. In step S2, the film sensitivity SV detected by the film information detection circuit 25 is read out, and in step S3, the guide number GN (ISO100) of the electronic flash device stored in advance in the control circuit 21 is read out.

Next, in step S4, distance measurement is performed through the distance measurement circuit 24, and the three obtained object distances D1 to D3 are obtained.
Enter. In step S5, the reference subject distance D is calculated from the subject distances D1 to D3 by the following equation. D = 1.4 × Min (D1 to D3) (where Min (D1 to D3) is the minimum value of D1 to D3) For example, in the example of FIG. 5, Min (D1 to D3) = D1, so D = It becomes 1.4 × D1. Next, in step S6, the aperture value AV is calculated from the guide number GN, the film sensitivity SV and the reference subject distance D by a time equation.

[Equation 1] The aperture value AV is a value at which the subject located at the reference subject distance D is photographed with proper exposure when the transmittance of the EC element is 100%. AV and SV are values according to the APEX method, and SV = 5 when ISO100.

Next, in step S7, each EC element 16
The transmittances T1 to T3 of a to 16c are obtained as follows. When Di (i = 1 to 3) ≧ D; Ti = 100 (%) When Di <D; Ti = (Di / D) ² × 100 (%) (1) According to this, When the subject distance Di is shorter than the reference subject distance D, the transmittance Ti is calculated by the above equation based on the subject distance Di and the reference subject distance D. The transmittance Ti becomes smaller as the subject distance Di becomes shorter. For example, in the example of FIG. 5, since D1 to D3 are all less than D, T1 to T3 are all calculated from the above equation (1). Next, at step S8, the EC elements 16a to 16a are adjusted so that the calculated transmittance Ti is obtained.
Apply voltage to c.

Then, in step S9, the full-press switch S is pressed.
When it is determined that W2 is off, the process proceeds to step S10, when it is determined that half-push switch SW1 is on in step S10, the process returns to step S9, and when it is determined that it is off, the process ends. When it is determined in step S9 that the full-press switch SW2 is turned on, flash photography is performed in step S11. That is, an unillustrated aperture is driven via the exposure control circuit 26 so as to have the aperture value AV calculated above, and the shutter is opened. When the shutter is fully opened, the three emission lights of the electronic flash device are emitted via the emission control circuit 23. The parts are fully illuminated at the same time. After that, when a predetermined shutter time has elapsed, the shutter is closed.

According to the above procedure, when the release button 17 is pressed halfway during a flash photography command, distance measurement is performed on the three distance measurement areas 51a to 51c, and object distances D1 to D3 are detected. At the same time, the reference subject distance D is obtained from these subject distances D1 to D3. Then, the aperture value AV is calculated from the reference subject distance D, the guide number GN of the electronic flash device, and the film sensitivity SV. On the other hand, the reference subject distance D and the subject distances D1 to D3
The transmittances T1 to T3 of the respective EC elements 16a to 16c are obtained from the above, and the EC elements 16a to 1 are adjusted so as to have the transmittances.
6c is controlled.

After that, when the release button 17 is fully pressed, flash photography is performed. At this time, the illumination light from each light emitting unit passes through the EC elements 16a to 16c whose transmittance is controlled and is guided to the subject in each of the illumination regions 50a to 50c in the field, so that the illumination regions 50a to 50c The amount of illumination light is E
It is adjusted according to the transmittances T1 to T3 of the C elements 16a to 16c. Here, the transmittances T1 to T3 are smaller as the subject distances D1 to D3 of the subjects located in the respective illumination regions 50a to 50c are smaller as described above, so that the closer the subjects are, the smaller the amount of illumination light guided. Specifically, as shown in FIG. 5, D1 <D3 <D2 (where D1
1, D3, D2 <D), T1 <T3 <T2, and the amount of light guided to each of the subjects O1, O2, O3 is O.
1, O3, O2 decrease in order. Since the illumination light amount of each subject is adjusted according to the subject distance in this way, it is possible to perform flash photography of all the subjects O1, O3, O2 with proper exposure.

In the configuration of the above embodiment, the EC device 1
6a to 16c constitute a light amount adjusting means, the distance measuring circuit 24 constitutes a multi distance measuring means, and the control circuit 21 and the EC driving circuit 22 constitute a transmittance controlling means.

The formula for obtaining the transmittance is not limited to the above formula, and any other formula may be used as long as the transmittance becomes smaller as the subject distance Di becomes shorter. Also, the formula for obtaining the reference subject distance D is not limited to the embodiment. Furthermore, in the above, the example in which the illumination area is divided into three has been shown, but the illumination area may be divided into four or more areas. In this case, it is necessary to provide four or more EC elements corresponding to each area and also provide four or more distance measurement areas. Furthermore, the light amount adjusting means is not limited to the EC element, and a liquid crystal element or another element may be used instead of the EC element.

Although an example using the active autofocus distance measuring means has been shown, a passive method or another distance measuring method may be used as long as each object distance can be detected. Further, although the electronic flash device having three light emitting portions for illuminating each of the three illumination regions is used, an electronic flash device having one light emitting portion for illuminating the entire field may be used, and in this case, the light amount adjustment is also performed. By means of the means, it is possible to independently adjust the amount of illumination light of a plurality of illumination areas in the object scene.

[0021]

According to the present invention, in a flashmatic camera, the amount of illumination light for illuminating each illumination area in the object scene is independently determined based on a plurality of subject distances obtained by multi-distance measurement and a reference subject distance. Since the adjustment is made, it becomes possible to perform flash photography with proper exposure for all of a plurality of subjects located at different distances.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control system of a flashmatic camera according to an embodiment of the present invention.

FIG. 2 is a perspective view of the flashmatic camera as seen from the front.

FIG. 3 is a diagram showing each illumination area and a distance measuring area in the object scene.

FIG. 4 is a diagram showing a relationship between an applied voltage and a transmittance of an EC element.

FIG. 5 is a diagram illustrating a multi-distance measurement method.

FIG. 6 is a flowchart showing a processing procedure for flash photography control.

[Explanation of symbols]

 11 camera body 16 light emission windows 16a to 16c EC element 17 release button 19 light emission mode switching button 21 control circuit 22 EC drive circuit 23 light emission control circuit 24 distance measuring circuit 25 film information detection circuit 26 exposure control circuit 30 distance measuring section 50 subject Field 50a to 50c Illumination area 51a to 51c Distance measuring area D Reference subject distance D1 to D3 Subject distance O1 to O3 Subject

Claims (1)

[Claims] 1. A flashmatic camera which calculates a diaphragm value for obtaining a proper exposure from a guide number of a flash device and a reference subject distance, and sets a diaphragm to the calculated diaphragm value to perform flash photography. A light amount adjustment, which is composed of a plurality of members having variable light transmittances, transmits the illumination light of the flash device and guides the illumination light to the object field, thereby independently adjusting the amount of illumination light of the plurality of illumination areas in the object field. Means, a multi-distance measuring means for independently distance-measuring objects respectively located in the plurality of illumination regions, and prior to flash photography, based on the reference object distance and each distance-measuring output of the multi-distance measuring means, A flashmatic camera, comprising: a transmittance control means for controlling the transmittance of each light quantity adjusting means.