Title:
METHOD AND DEVICE FOR AUTOMATIC EXPOSURE CONTROL FOR PHOTOGRAPHIC CAMERA
Document Type and Number:
Japanese Patent JPS5579421
Kind Code:
A
Abstract:
Disclosed is a method and apparatus for automated exposure control in a photographic camera having a lens equipped with an automatically adjusting diaphragm. A measuring signal is provided which is proportional to the luminance of the subject, the sensitivity of the film and the initial aperture at which the diaphragm is set. A control device is provided which stops the moving aperture at its working opening. A reference signal is provided by combining the measuring signal with a signal proportional to a shutter speed limit value. The diaphragm automatic adjustment is initiated and the variation or change in diaphragm aperture is converted to a signal which is combined with the measuring signal. This varying signal is continuously compared with the reference signal and a control signal to stop the automatic adjustment of the diaphragm is issued when the signals being compared are equal. In one embodiment of the invention, the reference signal is provided by combining the measuring signal and the shutter speed limit value in a 1-to-1 ratio. This ratio can be changed to provide either shutter speed or aperture priority if desired.
Inventors:
RORUFU MAAGERU
Application Number:
JP15195379A
Publication Date:
June 14, 1980
Filing Date:
November 22, 1979
Export Citation:
Assignee:
LEITZ ERNST GMBH
International Classes:
G03B7/085; G03B7/081; G03B7/087; (IPC1-7): G03B7/085; G03B7/087
Domestic Patent References:
| JPS5332731A | 1978-03-28 |