Title:
【発明の名称】ズームレンズ
Document Type and Number:
Japanese Patent JP2814388
Kind Code:
B2
Abstract:
A zoom lens comprises, in succession from the object side, a first lens group (G1) having a positive refractive power, a second lens group (G2) having a negative refractive power, a third lens group (G3) having a positive refractive power, and a fourth lens group (G4) having a positive refractive power. The zoom lens is designed such that during the zooming from the wide angle end to the telephoto end, all of said lens groups are moved toward the object side along the optical axis, and during the focusing on an infinity object to a short distance object, the third lens group (G3) and the fourth lens group (G4) are moved toward the image side while having the spacing therebetween relatively varied. The zoom lens is further designed to satisfy the following condition: beta 3T . beta 4T < beta 3W . beta 4W < - 1.3 where beta 3W and beta 4W are the lateral magnifications of the third lens group and the fourth lens group, respectively, in the infinity in-focus state of the wide angle end, and beta 3T and beta 4T are the lateral magnifications of the third lens group and the fourth lens group, respectively, in the infinity in-focus state of the telephoto end.
Inventors:
Atsushi Shibayama
Application Number:
JP16464089A
Publication Date:
October 22, 1998
Filing Date:
June 27, 1989
Export Citation:
Assignee:
NIKON CORPORATION
International Classes:
G02B13/18; G02B15/16; G02B15/173; G02B15/20; (IPC1-7): G02B15/20; G02B13/18
Domestic Patent References:
| JP6240412A | ||||
| JP6014212A | ||||
| JP58143312A |
Attorney, Agent or Firm:
Takao Watanabe