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:
May. 15, 1990
Filed:
Aug. 04, 1989
Masaharu Kawamura, Kanagawa, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A camera is provided with automatic focusing circuitry which is arranged to begin to operate to drive a focusing motor, in response to an operation performed on a shutter release button, to bring the motor to a stop upon detection of an in-focus state and to produce an in-focus signal. Photometric circuitry is arranged to begin to operate in response to the operation on the release button to obtain a photometric value by detecting the luminance of an object to be photographed, and to be capable of renewing the photometric value in response to a change in the luminance of the object. The photometric value is locked in response to the generation of the in-focus signal. Control circuitry means which controls the photometric apparatus in response to cancellation of the operation on the release button. The control circuitry unlocks the photometric value kept at the photometric apparatus and allows the photometric apparatus to operate to obtain another photometric value by detecting the luminance of the object once more within a predetermined period of time.