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:
Dec. 29, 1998
Filed:
May. 20, 1997
Shinichi Tsukada, Toride, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A focus setting system for a camera in which a photographer can observe a focused subject image in a viewfinder and which corrects the focus prior to exposure such that a photographed picture is in focus. Specifically, the focusing system corrects for errors introduced by varying apertures. The focusing system has a photographic lens which has a memory for storing focus error data which represents focusing adjustment values from an open aperture to a number of predetermined apertures. A focus detection device detects a focused state of the photographic lens using a portion of the incident light rays of the photographic lens. A first drive unit drives the photographic lens by calculating a focus drive amount which achieves focus at open aperture. The focus drive amount is calculated from the focus error data and the focus state detected by the focus detection device. A second drive unit drives the photographic lens by calculating a second focus drive amount which sets the focus for a predetermined aperture based on the focus error data and the focused state detected by the focus detection device.