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: An apparatus for activating an electronic flash by operating an X contact when the first blind of a focal plane shutter has terminated its movement to fully open an exposure light path, irrespective of an exposure period establishing operation. Where an electronic focal plane shutter is combined with an auto-strobo, a photometric circuit within the electronic circuit is used to measure the radiation from the auto-strobo, and to control the amount of exposure to a proper value. Where a proper amount of exposure is available by natural light when the shutter is opened, a closing movement of the shutter is utilized to cause the trigger capacitor of the electronic flash to be discharged, thereby disabling the illumination of the electronic flash.

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.

Abstract: An apparatus for activating an electronic flash by operating an X contact when the first blind of a focal plane shutter has terminated its movement to fully open an exposure light path, irrespective of an exposure period establishing operation. Where an electronic focal plane shutter is combined with an auto-strobo, a photometric circuit within the electronic circuit is used to measure the radiation from the auto-strobo, and to control the amount of exposure to a proper value. Where a proper amount of exposure is available by natural light when the shutter is opened, a closing movement of the shutter is utilized to cause the trigger capacitor of the electronic flash to be discharged, thereby disabling the illumination of the electronic flash.