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:
Aug. 25, 1981
Filed:
Oct. 02, 1979
Joseph M Canter, Lexington, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
A photometer for use in combination with a camera determines the optimum film exposure interval with the exposure interval corrected for differences in illuminance between a subject of principal interest in the central portion of the scene to be photographed and the subjects of secondary interest in the foreground and background portions of the scene. The photometer includes a photo-responsive array divided into three light receiving segments each having a field of view that generally corresponds to, respectively, the central portion, the foreground portion, and the background portion of the scene. Electronic circuitry, either in analog or digital form, is provided to select the maximum output of the background and foreground segments of the photo responsive array and compare the so-selected maximum output with the output of the central segment to increase the exposure interval when either the background or the foreground portion of the scene are more brightly illuminated than the subject of principal interest and decrease the exposure interval when the background or foreground portion of the scene are less brightly illuminated than the subject of principal interest. A photometer in accordance with the present invention is suitable for use with both conventional shutter mechanisms and time-integrating shutters.