Title:
SMALL ZOOM LENS
Document Type and Number:
Japanese Patent JPH04161914
Kind Code:
A
Abstract:
PURPOSE:To reduce the production cost by constituting a zoom lens with the first lens group having positive refracting power and the second lens group having negative refracting power in sequence from the object side, containing at least one a spherical lens in both lens groups, and using a plastic lens with weak refracting power for one of them. CONSTITUTION:This zoom lens is constituted of the first lens group with positive refracting power and the second lens group with negative refracting power in sequence from the object side. The first lens group is constituted of a negative-meniscus lens with the convex face faced to the object side, a negative- meniscus lens with the concave face provided on the object side, a plastic lens having an aspherical face with weak refracting power and a lens with positive refracting power in sequence from the object side. The zoom lens has a variable power ratio of about two from the quasi-wide angle to quasi-telescope, and the production cost can be reduced while maintaining good image forming performance.
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Inventors:
OTA KOHEI
Application Number:
JP28591290A
Publication Date:
June 05, 1992
Filing Date:
October 25, 1990
Export Citation:
Assignee:
KONISHIROKU PHOTO IND
International Classes:
G02B13/18; G02B15/16; (IPC1-7): G02B13/18; G02B15/16
Attorney, Agent or Firm:
Fumio Sato (2 others)