JPH02120832A - Camera with exposure control device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a camera that can be equipped with a wide converter.
In particular, the present invention relates to a camera equipped with a means for correcting light amount loss when the strobe illumination angle is widened.

[Prior Art] Conventionally, a wide converter lens or a teleconverter lens that can be attached to the front of a camera body equipped with a main photographing lens is known as an attachment lens that expands the photographing area of a camera.

[Problem to be solved by the invention] When the wide converter is installed, the shooting angle of view is expanded, so the COS4
The amount of light at the periphery of the photographic lens decreases according to a multiplicative law, and furthermore, when using a strobe, the irradiation angle of the strobe is insufficient at the periphery, resulting in extremely underexposure at the periphery.

In particular, in contrast to conventional silver halide film cameras, electronic cameras using solid-state image sensors are required to have higher resolution.
Since the focal length of the main shooting lens is set relatively long,
There is a high demand for wide converter lenses, and in this case, because the latitude is narrower than that of silver halide film, insufficient light at the periphery during strobe photography is unacceptable in practical use.

Conventionally, it has been known that one way to solve this problem is to attach a wide panel to the front of the strobe on the camera body to widen the illumination angle, but the total amount of light remains unchanged Since the light is diffused throughout the area, there is a problem in that the illuminance at the center decreases. The amount is 35% of the silver halide film.
When converting the irradiation angle equivalent to a 28mm lens to the irradiation angle equivalent to a 28mm lens, the angle at the center is 1.5 to 2. This will result in a decrease in OEV.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a camera in which a wide converter can be attached in front of the main photographing lens. and (b) means for detecting attachment of the wide converter, and the wide converter has a wide panel disposed in front of the strobe of the camera body when attached;
In such a configuration, when the wide converter is installed, the detection means applies correction to the control means.

[Embodiment] FIG. 1 is a configuration diagram showing an embodiment of the present invention. In the figure, 1 is a camera body, 2 is a main photographing lens, 3 is a half-open lens shutter diaphragm, and 4 is a strobe light emitting section. Reference numeral 10 denotes a light emission control circuit having a trigger circuit and the like for starting light emission from the strobe light emitting section, and the strobe device is assumed to perform full light emission. 11 is an exposure control circuit that controls the aperture 3; 12 is an exposure control circuit that sends out a command to start the strobe device;
This is a microcomputer that determines the flash aperture based on the guide number of the strobe and the distance to the subject detected by the distance detection means 13 and controls the entire sequence. 14 is a correction means for shifting the aperture determined by the microcomputer 12 to the open side by a predetermined amount;
Reference numeral 5 denotes a wide converter installation detection switch, and when the switch is turned on, the microcomputer 12 is notified of the installation of the wide converter, and the correction means 14 is activated by the microcomputer 12.

6 is a wide converter main body, 7 is a wide converter lens, 8 is a wide panel located in front of the light emitting part of the strobe, and 9 is a protrusion that turns on the switch 5 when the converter main body 6 is attached to the camera.

Next, the operation of the embodiment shown in FIG. 1 will be explained using the flowchart shown in FIG.

Assume that the flash mode is currently set. In this state, the microcomputer 12 operates according to the flow shown in FIG.

In step 1, the subject distance information detected by the distance detection means 13 and the guide number of the strobe device are calculated to determine the aperture value for flash. In step 2, the state of the switch 5 is detected, and when the switch is off, that is, when the converter 16 is not installed, the process proceeds to step 4 and exposure control is performed.

Therefore, when the converter 9 is not installed, the aperture is the aperture calculated in step 1 above, and flash photography is executed in that state.

On the other hand, when the converter 6 is installed, the switch 5 is turned on, so the process proceeds to step 3, where an aperture value that is shifted by a predetermined amount to the open side with respect to the aperture value obtained in step 1 is obtained, and in step 4 , Flash photography is performed at this aperture.

As described above, when the converter is installed, the aperture is shifted to the open side, so that the insufficient amount of light emission can be automatically corrected.

Note that the distance detection means 13 may output distance information in conjunction with a distance ring, or may output distance information detected by an autofocus device.

Furthermore, although the above embodiment is of a type that corrects the aperture, if the present application is applied to a type that controls the amount of light emitted by a light control sensor, an optical system different from that of the photographic lens must be used when attaching the converter. If you reduce the output of the light control sensor that receives the light that passes through the lens, shift the aperture as in the above embodiment, or place the light control sensor in a position that receives the light that passes through the photographic lens. The configuration may be such that the aperture is shifted to the narrowing side.

[Effects of the Invention] As described above, according to the present invention, when using a wide converter, it is possible to provide uniform artificial illumination over the entire screen in indoor strobe photography, and it is also possible to compensate for the lack of light emission in automatic fishing. , optimal exposure control can be performed in the same way as when the wide converter is not installed.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a camera having an exposure light amount correction neck device according to the present invention, and FIG. 2 is an explanatory diagram showing a flowchart explaining the operation of the camera shown in the first diagram. 6...Wide converter body 5...Switch 14...Correction means

Claims (1)

[Scope of Claims] A camera equipped with a control circuit that controls the amount of exposure or the amount of flash so as to obtain the optimum amount of image surface light for the amount of light emitted by a strobe during flash photography, which is mounted on the front of the main photographing lens of the camera. and detecting means for detecting the attachment of a wide converter having a wide panel located in front of the light emitting part of the strobe when attached to the front of the main photographing lens, and the control circuit by detecting the attachment of the converter by the detection means. 1. A camera equipped with an exposure control device, characterized in that a correction circuit is provided for shifting a control amount by a predetermined amount with respect to a control amount.