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Title:
WIDE-ANGLE LENS, OPTICAL APPARATUS, AND METHOD FOR FOCUSING WIDE-ANGLE LENS
Document Type and Number:
Japanese Patent JP2009193053
Kind Code:
A
Abstract:

To provide a wide-angle lens having higher optical performance, an optical apparatus using thereof, and a method for focusing the wide-angle lens.

The wide-angle lens includes, in order from an object, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having positive refractive power. Upon focusing to an object, the first lens group G1 is fixed, and the second lens group G2 and the third lens group G3 are moved to the object side. The second lens group G2 includes a negative refractive power lens component L21 to the most object side, and the following conditional expression is satisfied: -f1/f6.00, where f denotes a focal length of the entire system, and f1 denotes a focal length of the first lens group G1.


Inventors:
HARADA MASAKI
Application Number:
JP2008000291344
Publication Date:
August 27, 2009
Filing Date:
November 13, 2008
Export Citation:
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Assignee:
NIKON CORP
International Classes:
G02B13/04; G02B13/18; G03B5/00
Domestic Patent References:
JPH0933801A1997-02-07
JP2004245966A2004-09-02
JPS62206513A1987-09-11
Attorney, Agent or Firm:
井上 義雄