Olympus Optical Company, Ltd.

Muneaki Yoshida

Yoshihisa Maitani

Akihiko Hashimoto

Masahiro Kitagawa

Kunio Shimoyama

Yukio Nakajima

Masafumi Yamasaki

Hiroshi Yamada

Satoshi Kawakami

In this strobo apparatus, in a strobo controlling circuit in which such self-arc extinction-type gate-controlling type switching device as an IGBT is connected in series with a flash discharge tube to control the flash of the discharge tube, a bias voltage controlling the on/off operation of the above-mentioned gate-controlling type switching device is obtained from a biasing condenser charged with an exciting current of the flashing discharge tube or directly from a power source voltage boosting circuit through a resistance or sub-condenser.

Strobo apparatus

Disclosed is a single lens reflex camera of the mean metering type having a first photodiode provided between a mirror and a film and a second photodiode provided in a finder system in which before the shutter release a shutter time is calculated on the basis of an output signal of the second photodiode and is displayed in the finder, and when the shutter release starts and the mirror rises and the shutter time is determined by an output signal from the first photodiode for receiving the reflected light from a front shutter curtain and the film. In the camera, a central portion of the mirror is translucent. A submirror is provided behind the translucent portion, which causes the first photodiode to receive the light from only the central portion of a frame before the shutter release. Further, the camera has a first operating circuit for obtaining a difference between the outputs from the first and second photodiodes before the shutter release and a second operating circuit for adding the result of the operation by the first operating circuit to the output from the first photodiode during the shutter release, whereby a partial metering for controlling a shutter time during the shutter release in accordance with the result of the operation by the second operating circuit is realized.

Automatic exposure control camera

A photometric apparatus for single lens reflex camera and of the type in which an exposure value is determined by photometry of light which is transmitted through a photographic optical system and is reflected by at least one of the surfaces of a shutter blind and a film, said apparatus comprising a photoelectric transducer element for receiving light reflected by at least one of the surfaces of a shutter blind and a film, and an operational amplifier for biasing the photoelectric transducer element to maintain the voltage applied thereacross substantially null, thereby enabling a photometric output of the photoelectric transducer element to be effectively derived even when the amount of light received is minimal. A second photoelectric transducer element is provided for receiving reflected light from the reflecting mirror that is adapted to be switched between the viewfinder light path and the photographic light path and display means for displaying the operation of the shutter dependent upon the light which is incident upon the aforesaid second transducer element.

Photometric apparatus for single lens reflex camera

A photometric apparatus for single lens reflex camera and of the type in which an exposure value is determined by photometry of light which is transmitted through a photographic optical system and is reflected by at least one of the surfaces of a shutter blind and a film, said apparatus comprising a photoelectric transducer element for receiving light reflected by at least one of the surfaces of a shutter blind and a film, and an operational amplifier for biasing the photoelectric transducer element to maintain the voltage applied thereacross substantially null, thereby enabling a photometric output of the photoelectric transducer element to be effectively derived even when the amount of light received is minimal. The shutter blind is provided with a surface upon which at least two portions thereof have different coefficients of reflectivity to reduce adverse effects of reflected light upon the desired exposure period.

A photometric apparatus for single lens reflex camera and of the type in which an exposure value is determined by photometry of light which is transmitted through a photographic optical system and is reflected by at least one of the surfaces of a shutter blind and a film, said apparatus comprising a photoelectric transducer element for receiving light reflected by at least one of the surfaces of a shutter blind and a film, and an operational amplifier for biasing the photoelectric transducer element to maintain the voltage applied thereacross substantially null, thereby enabling a photometric output of the photoelectric transducer element to be effectively derived even when the amount of light received is minimal. The photometric apparatus, including a photoelectric transducer element, a photometry switch and associated circuitry are mounted upon a printed circuit board mounted within the camera to position the transducer element to receive reflected light from the film or the shutter.

A photometric apparatus for single lens reflex camera and of the type in which an exposure value is determined by photometry of light which is transmitted through a photographic optical system and is reflected by at least one of the surfaces of a shutter blind and a film, said apparatus comprising a photoelectric transducer element for receiving light reflected by at least one of the surfaces of a shutter blind and a film, and an operational amplifier for biasing the photoelectric transducer element to maintain the voltage applied thereacross substantially null, thereby enabling a photometric output of the photoelectric transducer element to be effectively derived even when the amount of light received is minimal.

Growing community of inventors

Hachioji, Japan

Muneaki Yoshida