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:
Jul. 27, 1993
Filed:
Dec. 09, 1991
Nikon Corporation, Tokyo, JP;
Abstract
A camera system and a rear conversion lens both of which accurately calculate the distance .DELTA.X a focusing lens moves when the rear conversion lens is interposed between an interchangeable lens and the camera body, even when the distance .DELTA.Bf an image surface of the focusing lens shifts, increases, so that a subject can be focused quickly. A factor K.sub.0 for converting the distance the image surface of an interchangeable lens shifts and a factor C.sub.0 for correcting the conversion factor K.sub.0 are stored, and the magnification .beta.c and the focal length fc of the rear conversion lens are also stored independently of the above two factors. The distance .DELTA.X is calculated with precision. The subject can thus be automatically focused smoothly and quickly.