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Title:
ZOOM FINDER
Document Type and Number:
Japanese Patent JPH02116811
Kind Code:
A
Abstract:
PURPOSE:To obtain the zoom finder which is high in magnification and is good in ease of viewing without enlarging the external form by making variable power by constituting the zoom finder in such a manner that variable power is made by the movement of a 1st lens and 2nd lens on the optical axis, parallax correction is made by the movement of a parallel plane plate in the direction perpendicular to the optical axis and specific conditions are satisfied. CONSTITUTION:The variable power is made by the movement of the 1st lens and the 2nd lens on the optical axis and the parallax correction is made by the movement in the direction perpendicular to the optical axis of the parallel plane plate. This zoom lens is so constituted as to satisfy the conditions expressed by the equations I to V. In the formulas I to V, f1 denotes the focal length of the 1st lens; f2 denotes the focal length of the 2nd lens; LDt denotes the overall length of the lens at the time of a narrow visual field and high magnification; R2 denotes the paraxial radius of curvature of the 2nd lens; R3 denotes the paraxial radius of curvature of the 3rd face. The zoom finder which is well corrected in various aberrations and is good in the ease of viewing is obtd. in this way while the zoom lens is small in size and is high in magnification.

Inventors:
SUGAWARA SABURO
Application Number:
JP27038488A
Publication Date:
May 01, 1990
Filing Date:
October 26, 1988
Export Citation:
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Assignee:
ASAHI OPTICAL CO LTD
International Classes:
G03B13/12; G02B13/18; G02B15/00; G02B15/14; G02B15/17; G02B23/14; G02B25/00; G03B23/14; (IPC1-7): G02B15/14; G03B13/12; G03B23/14
Domestic Patent References:
JPS6187112A
JPS61160712A
JPS60222381A
JPS64512A



 
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