Seikosha Co., Ltd.

Katsuhiko Matsushita

Kazuo Akimoto

Shigeru Tagami

Kanji Ito

Hiroyuki Saito

Nobuo Shinozaki

Tadashi Nakagawa

Hiroshi Yamazaki

Miyoshi Tanikawa

Hiroyuki Koizumi

A camera shutter system includes a matrix memory, an arrangement for determining the initial speed of a shutter sector, and a source of exposure values. The memory stores shutter-exposure pulse data elements, and is addressed by functions of the determined speed and the exposure values. A motor coupled to the sector is controlled in response to an accessed pulse data element. The data elements may relate only to variable portions of movement of the shutter, and be added to fixed values in order to minimize the size of the memory.

Camera shutter

A camera shutter system has a motor driven sector for opening and closing a shutter opening. A photo-interruptor is positioned to intercept a light beam, to effect the outputting by the photo-interruptor of a signal pulse corresponding to the speed of the shutter. A memory storing exposure data, such as a matrix memory, is accessible as a function of the speed signal and an exposure quantity that is a function of the brightness of the brightness of an object to be photographed. The accessed exposure data is modified as a function of an observed exposure quantity.

Arrangement for compensating for variable speed of a camera shutter

A camera shutter system has a motor driven sector for opening and closing a shutter opening. A photo-interruptor is positioned to intercept a light beam, to effect the generation of a photo-interruptor signal. A timer has a counter that is set to a first count in response to the photo-interruptor signal, and is reset when a given count is reached. A shutter malfunction signal is generated when the level of the photo-interruptor signal has not changed by the time the given count is reached.

A camera shutter system has a motor driven sector for opening and closing a shutter opening. A photo-interruptor is positioned to intercept a light beam, to effect the sequential generation of first and second photo-interruptor signal pulses, the first pulse having a width that is a function of the speed of the sector. A timer has a counter that is set to a first count corresponding to an exposure value that is a function of the brightness of an object to be photographed and the width of the first photo-interruptor signal. The timer is controlled to count down in response to the second photo-interruptor signal, and the sector driving motor is energized during the count down of the timer.

A camera having a lens shutter and a focal-plane shutter, includes a selector circuit for selecting either a lens shutter mode or a focal-plane shutter mode; a first driving device for controlling either the programmed exposure value of the lens shutter or the size of the aperture, the first driving device including a motor and an actuating member driven by the motor, the actuating member including a peripheral surface with a first cam for controlling the programmed exposure value of the lens shutter in response to forward rotation of the motor, and a second cam for controlling the size of the aperture in response to reverse rotation of the motor, the first cam having an inclination in a first direction and the second cam having a less steep inclination in an opposite direction; a pivotally mounted opening lever connecting the lens shutter to the actuating member, the lever defining a first arm and a second arm, the first arm in engagement with the actuating member and the second arm connected with the lens shutter, a first pin on the first arm which rides on the cams, and a second pin on the second arm to pivotally connect with shutter blades of the lens shutter; a spring biasing the first pin into engagement with the cams; a second driving device controlling the time of operation of the focal-plane shutter mode; and a sequential control circuit controlling the driving devices.

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Chiba, Japan

Katsuhiko Matsushita