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:
Jun. 09, 1998
Filed:
Nov. 22, 1993
Seiji Shimizu, Tokyo, JP;
Tatsuru Kanamori, Tokyo, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
A zoom lens system having three lens units, that is, a negative lens unit, a positive lens unit, and a negative lens unit. The idea of floating system is introduced into the rear focusing system to minimize the degree of aberration fluctuation at a short object distance with a simple lens arrangement, thereby stabilizing the optical performance during focusing at a short object distance. The zoom lens system includes a 1-st lens unit (G1) having a negative refractive power, a 2-nd lens unit (G2) having a positive refractive power, and a 3-rd lens unit (G3) having a negative refractive power, and effects zooming from the wide end to the tele end by varying the spacing between each pair of adjacent lens units. With the 2-nd lens unit (G2) defined as a focusing lens unit, focusing is effected by varying the axial air spacing between a lens component (L.sub.F) of the 2-nd lens unit (G2) that is the closest to the image side and the remaining lens component (L.sub.F ').