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Patent Searching and Data


Title:
ZOOM LENS SYSTEM
Document Type and Number:
Japanese Patent JPH11109238
Kind Code:
A
Abstract:

To realize high variable power rate and high image quality by specifying the ratio of a focal distance in a shortest focal distance state to the focal distance in a longest focal distance state.

In this zoom lens system provided with a 1st lens group Gr1 having positive power, a 2nd lens group Gr2 having negative power and a 3rd lens group Gr3 having the positive power in order from an object side; at least the 1st lens group Gr1 is moved to perform zooming. Then, the system is constituted to satisfy an expression: 1<max(T1, T2, T3)<fw<4 and an expression: 4.5<ft/f12w<15. In the expressions, Ti means the thickness of the i-th group on an optical axis and max(T1, T2, T3) means the maximum value thereof, (fw) means the focal distance in the shortest focal distance state, (ft) means the focal distance in the longest focal distance state, f12w means the synthetic focal distance of the 1st and the 2nd lens groups in the shortest focal distance state.


Inventors:
Arimoto, Tetsuya
Terada, Mamoru
Okada, Naoshi
Konno, Kenji
Kono, Tetsuo
Ishimaru, Kazuhiko
Application Number:
JP1997000265398
Publication Date:
April 23, 1999
Filing Date:
September 30, 1997
Export Citation:
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Assignee:
MINOLTA CO LTD
International Classes:
G02B13/18; G02B15/20; (IPC1-7): G02B15/20; G02B13/18