Photography – Exposure control circuit – Having plural photocells
Patent
1997-12-05
1999-03-23
Perkey, W. B.
Photography
Exposure control circuit
Having plural photocells
G03B 708
Patent
active
058872043
ABSTRACT:
Proper exposure is obtained even when the mirror down time is short, which occurs, for example, during continuous photography. This is achieved, for example, by determining the accumulation time and gain for a subsequent round of photometry based on whether a photometry prohibiting signal interrupted the current round of photometry. Additionally, the photometry parameters that are used for photometry can be changed (or set) based on changes in the film feed mode of the camera. The camera can include a photometry circuit that performs photometry on an object field using an accumulating type of photometry element. An accumulation controller controls the start and finish of the accumulation of the photometry element. A feed mode setting device is capable of setting a film feed mode from among a plurality of film feed modes. The plurality of film feed modes includes at least a high-speed mode in which the photographic (time) interval (between photographs) is short and a low-speed mode in which the photographic (time) interval is long. A photometry parameter determining device such as, e.g., a programmed micro-processor, determines the photometry parameters to be used for photometry based on the output of the feed mode setting device. Alternatively, or in addition, the photometry parameters are changed (or set) based on the status of the power source. A camera including this feature would have a status determining device that detects the camera operability status, in particular, the status of the power source. The photometry parameter determining device then determines the photometry parameters to be used for photometry based on the output of the status determining device.
REFERENCES:
patent: 3584961 (1971-06-01), Cason et al.
patent: 4281897 (1981-08-01), Fletcher
patent: 4460257 (1984-07-01), Ogasawara
patent: 4563069 (1986-01-01), Sakai et al.
patent: 4657368 (1987-04-01), Kawamura
patent: 5341220 (1994-08-01), Juen
patent: 5721977 (1998-02-01), Yamawaki et al.
patent: 5768540 (1998-06-01), Iwasaki
Nikon Corporation
Perkey W. B.
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