Abstract: 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.

Abstract: 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.

Abstract: A camera comprises a focal-plane shutter having a front curtain and a rear curtain. The front curtain comprises a center portion thereof being formed into a low reflection portion and a rear end portion being at least formed into a high reflection portion as compared with the center portion in the running direction of the front curtain.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.