Photography – Exposure control circuit – Manual av circuit with automatic tv circuit – or vice versa
Patent
1997-10-20
1999-02-23
Perkey, W. B.
Photography
Exposure control circuit
Manual av circuit with automatic tv circuit, or vice versa
396443, 396458, G03B 700, G03B 900
Patent
active
058753630
ABSTRACT:
A camera shutter is capable of switching between a spring-drive mode and a motor-drive mode through a single electromagnet without performing an exposure operation. A control circuit controls a stepping motor for rotating a driving ring and the electromagnet for controlling the opening and closing operations of the diaphragm. A control circuit operates in a mode in which a first switch is turned ON, and in another mode in which a second switch is turned ON. When the first and second switches are turned ON, a normal photographing operation can be performed. However, when the first switch is turned ON and then OFF while keeping the second switch OFF, a power supply stop signal is transmitted to the electromagnet so that a closing sector is released from its restrained condition allowing the shutter to return to its initial state. When a photographer presses a shutter button after changing the mode, a photographing operation can be performed in the changed mode without the necessity of completing an exposure operation in the first selected mode.
REFERENCES:
patent: 5202721 (1993-04-01), Kobayashi et al.
Akimoto Kazuo
Imano Seiichi
Perkey W. B.
Seiko Precision Inc.
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