The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 12, 1982
Filed:
Nov. 14, 1979
Rolf Magel, Fernwald, DE;
Ernst Leitz Wetzlar GmbH, Wetzlar, DE;
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.