JPS626231A - Range finder and photometer for single-lens reflex camera - Google Patents

Abstract

PURPOSE:To attain plural purposes of range measurement and light measurement by simple constitution by providing the 1st photodetection part for obtaining light measurement information and the 2nd photodetection part for obtaining exposure information in the body of a single-len reflex camera and allowing a submirror to move so that subject light is guided to the 1st and the 2nd photodetection parts. CONSTITUTION:When the subject light l is incident on a photographic lens 1, this subject light l is reflected by a main mirror 2 to a finder optical system and light passes through the half-mirror part of the main mirror 2 is reflected by the submirror 4. The submirror 4 is normally at a solid-line position (1st position) to guide light l1 passed through the main mirror 2 to a photodetection part 5 for range measurement, and this light l1 is used for automatic focus control or range measurement. When light is measured, the submirror 4 is moved from the solid-line position to a broken-line position (2nd position) to guide light l2 and light l3 passes through the main mirror to a photodetection part 6 for light measurement, and the light l3 is used for exposure control.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a distance measuring/photometering device for a single-lens reflex camera, and in particular to a main mirror for a finder having a semi-transparent part, and a main mirror for a viewfinder having a semi-transparent part, and a main mirror for a finder having a semi-transparent part. The present invention relates to a camera equipped with a sub-mirror that guides light to a light-receiving element for distance measurement and photometry within a camera body.

(Background of the Invention) Conventionally, devices have been proposed that perform TTL photometry by also using a light receiving element for TTL distance measurement provided in a camera body. The light receiving element for this TTL distance measurement is usually
A dimensional image sensor or the like is used, and information from the subject is obtained from an extremely narrow and elongated part that corresponds to the split image part of the finder screen.

If you try to use such a photodetector for TTL photometry as well, the photometry information for T;rL photometry will also be obtained from this narrow and elongated area, and in such a photometry area, the photometry value will vary depending on the part of the subject being photometered. It has the disadvantage that it is difficult to use as a photometric device because it tends to fluctuate greatly. Furthermore, since this light-receiving element is made to exhibit performance as a distance-measuring device, it has the disadvantage that sufficient performance cannot be obtained as a light-receiving device for photometry.

(Objective of the Invention) It is an object of the present invention to solve this drawback and provide a distance measurement/photometering device that is capable of distance measurement and photometry, and can also obtain a large photometry output during photometry.

(Summary of the Invention) The present invention provides: - A first light receiving section for obtaining photometric information and a second light receiving section for obtaining exposure information are exclusively provided in the body of an eye-flex camera; The technical point is that the submirror is movable so as to guide the subject light to the first light receiving section and the second light receiving section.

(Embodiment) FIG. 1 is an embodiment of the present invention, and shows a layout diagram of an optical system of a camera. When object light l enters the photographic lens 1, this object light l is reflected by the main mirror 2 to the finder optical system, and the light that has passed through the semi-transparent part of the main mirror 2 is sent to the distance measuring light receiving part 5 by the sub mirror 4 ( Normally, the sub-mirror 4 is located at the position indicated by the solid line (first position N), and the sub-mirror 4 is reflected toward the photoreceptor 6 (first photoreceiver) or photoreceptor 6 (second photoreceiver), and the photoreceptor 5 for distance measurement The light 11 that has passed through the main mirror 2 is guided, and this light II is used for automatic focus control or distance measurement. In addition, during photometry, the sub-mirror 4 is moved from the position indicated by the solid line to the position indicated by the broken line (second position M), and the lights 12 and 13 that have passed through the main mirror 2 are guided to the light receiving section 6 for photometry, and from now on, i2 is used for exposure control. are doing. Further, when a strobe is attached to the camera, the light 13 reflected from the film surface 7 is used for TTL automatic light control exposure 11 control.

The sub-mirror 4, together with the main mirror 2, directs the subject light a during photography.
Since it is originally movably mounted, it is not so difficult to provide a mechanism to move it during photometry. For example, if you want to change from distance measurement control to light metering control, use the subject light! The direction of reflection is directed from the distance measurement light receiving section 5 to the photometry light receiving section 6.The submirror 4 is mechanically or electrically operated by the external operating member 8 to move from the position shown by the solid line to the position shown by the broken line. Just move it. At this time, when the operation member 8 is released from scratching, the sub-mirror 4 automatically returns to the position indicated by the solid line and the control for distance measurement is performed again. Further, when the control for distance measurement is switched to the control for photometry by the operation member 8, the processing circuit of the distance measurement system holds the distance measurement information signal so as not to output erroneous distance measurement information. It consists of

Further, since the photometry light receiving section 6 is directed toward the film surface 7, it can also be used for TTL automatic light adjustment exposure control when a strobe is attached to the camera.

Note that since the shape of the photometric area can be determined by the aperture shape of the photometric light receiving section 6, the aperture shape may be determined depending on the required photometric area.

With the above configuration, it is possible to select distance measurement and photometry according to the purpose with a simple configuration of moving the submirror 4. Since dedicated light receiving elements are used for distance measurement and photometry, highly accurate distance measurement and photometry are possible.

Furthermore, by arranging the light receiving element for distance measurement and photometry within the body, the space within the body can be effectively utilized.

(Effects of the Invention) As described above, according to the present invention, by providing a movable sub-mirror and providing the first and second light receiving sections, multiple purposes of distance measurement and photometry can be achieved with a simple configuration. realizable.

[Brief explanation of the drawing]

FIG. 1 shows a layout diagram of an optical system of a camera according to an embodiment of the present invention. (Explanation of symbols of main parts) 1...Photographing lens, 2...Main mirror 4...Sub mirror, 5...Light-receiving section for distance measurement, 6...Light-receiving section for photometry

Claims (1)

[Scope of Claims] A main mirror that reflects subject light to a finder system and has a semi-transparent section through which the subject light can pass, and a light receiving means in a mirror box that receives the subject light that has passed through the semi-transmissive section. In the camera, the light receiving means includes a first light receiving section for obtaining ranging information and a second light receiving section for obtaining exposure information, and the first light receiving section is When selected, the sub-mirror is moved to a first position so that the subject light enters the first light receiving section, and when the second light receiving section is selected, the subject light enters the second light receiving section. A distance measuring/photometering device for a single-lens reflex camera, characterized in that the sub-mirror is moved to a second position so that the light enters a light receiving section.