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. 05, 1983
Filed:
Nov. 15, 1976
Applicant:
Inventors:
Akira Tajima, Kawasaki, JP;
Sadahiko Tsuji, Yokohama, JP;
Assignee:
Canon Kabushiki Kaisha, , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
350422 ; 350427 ;
Abstract
The focal length at the telephoto end of a zoom lens is increased by making the magnification of the system .beta. with auxiliary focusing means while the ordinary focusing means of the zoom lens system is focused on infinity. An attachment lens having a focal length fA is provided in front of the zoom lens system in such a manner that the composite lens system is focused on infinity. The product fA .beta. of the magnification .beta. and the focal length fA of the attachment lens is longer than the focal length of the zoom lens.