Minolta Camera Kabushiki Kaisha

Mikio Naya

Yoshiharu Ohta

Hiroshi Hosomizu

Toshinori Imura

Keisuke Maeda

An automatic electronic flash device for use with a camera includes a flash tube carried by a housing. A battery is carried by the housing as a source of electric supply. A capacitor is connected to the flash tube to fire it when discharged. A circuit is used to automatically adjust the amount of light emitted from said flash tube upon the firing of the tube. The circuit includes a light receiving element arranged to receive light reflected from a photographic object upon the firing of the tube. The information of distance from the camera to an object to be photographed is fed to the circuit as a function of the amount of light received. A switch is connected to the circuit to cause it to vary the amount of light emitted from the flash tube. A calculator enables calculation of a plurality of combinations of aperture settings and distance setting in response to a film speed setting, so that selection of a desired film speed will result in indication of a desired aperture setting and distance setting. Light emitting diodes are disposed adjacent to the calculator for indication of one of the combinations calculated by the calculator. Another switch connects one of the light emitting diodes to the battery for selective energization thereof in association with the switching of the above switch connected to the circuit.

Automatically controlled electronic flash device

A semiconductor switching element is connected in series with a flash tube to stop emission of flash light therefrom during operation of the flash tube. A first and a second integrating circuit are parallelly arranged to be connected either alternatively, or both together, with the switching element. The first integrating circuit integrates photo-current generated by a photocell receiving light from an object illuminated by the flash light, and the second integrating circuit integrates current that is manually adjustable. When both integrating circuits are connected with the switching element, the switching element is turned off by that integrating circuit which first reaches a predetermined trigger level.

Electronic control circuitry for terminating flash output

A photoflash photography system includes a camera separably housing individual film cartridges carrying indicia, physical or electrical, representing the sensitivity of the film contained in the respective cartridge. A photoflash unit is coupled to the camera and has a light output which automatically varies inversely with the film sensitivity in response to the sensitivity indicia. The light output is varied by varying the charge voltage on the flash tube storage capacitor or the capacitor capacitance value. The electrical indicia may be resistors of different values and the physical indicia may be recesses of different depths or differently disposed shoulders or fingers which are detected by movable sensing members.

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Izumi, Japan

Mikio Naya