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Patent Searching and Data


Title:
LARGE-DIAMETER WIDE-ANGLE ZOOM LENS
Document Type and Number:
Japanese Patent JPH0682698
Kind Code:
A
Abstract:

PURPOSE: To provide the zoom lens which is compact and maintains high performance although the aperture ratio is about 2.8 as to a zoom lens which has a wide field angle of 74° or larger in maximum field angle.

CONSTITUTION: The zoom lens has a 1st negative group (L1), a 2nd positive group (L2), a 3rd negative group (L3), and a 4th positive group (L4) in order from an object side and is varied in the overall power while an image plane position is held constant by moving the 1st, 2nd, and 4th groups in the direction of the optical axis so that the air interval between the 1st and 2nd groups and the air interval between the 3rd and 4th group decrease and the air interval between the 2nd group and 3rd group increases at the time of zooming from the short-focus side to a long-focus side; and the 1st group is equipped with a 1st negative lens, a 2nd positive lens, a 3rd negative lens, and a 4th lens block which has at least one negative lens and is negative on the whole.


Inventors:
ASAKURA YOSHINOBU
Application Number:
JP23463792A
Publication Date:
March 25, 1994
Filing Date:
September 02, 1992
Export Citation:
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Assignee:
MINOLTA CAMERA KK
International Classes:
G02B13/18; G02B15/20; (IPC1-7): G02B15/20; G02B13/18