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Patent Searching and Data


Title:
PHOTOGRAPHING LENS FOR WHICH FLOATING IS UTILIZED
Document Type and Number:
Japanese Patent JPS63247713
Kind Code:
A
Abstract:

PURPOSE: To obtain the titled lens which is well corrected of an aberration fluctuation and has a large aperture ratio by allowing an optical system having 4 lens groups which have positive, positive, negative and positive refracting powers successively from an object side to make prescribed motion.

CONSTITUTION: This lens has the four lens groups consisting, successively from the object side, the 1st lens group 1 having the positive refracting power, a stop R7, the 2nd lens group II having the positive refracting power, the 3rd lens group III having the negative refracting power, and the 4th lens group IV having the positive refracting power. The 1st lens group I has at least one negative lens of which the strong concave face is directed to an image plane side. Focusing from an infinite object to a short distance object is executed by integrally extending the front lens group consisting of the 1st lens group I, the aperture Y7 and the 2nd lens group II and extending the 3rd lens group III at the moving quantity smaller than the moving quantity of the front lens group.


Inventors:
OGAWA HIDEKI
MATSUSHITA TAKASHI
Application Number:
JP8225187A
Publication Date:
October 14, 1988
Filing Date:
April 03, 1987
Export Citation:
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Assignee:
CANON KK
International Classes:
G02B9/64; G02B15/22; (IPC1-7): G02B9/64
Domestic Patent References:
JPS5848723A1983-03-22
JPS61238010A1986-10-23
JPS5948723A1984-03-21
Attorney, Agent or Firm:
Yukio Takanashi