Title:
ズームレンズ及びそれを有した光学機器
Document Type and Number:
Japanese Patent JP4401451
Kind Code:
B2
Abstract:
A zoom lens includes, in order from a longer conjugate side to a shorter conjugate side, a first lens unit of positive refractive power, a second lens unit of negative refractive power, and a succeeding lens group which is composed of a plurality of lens units or one lens unit and whose overall refractive power is positive, wherein, during zooming from a wide-angle end to a telephoto end, the separation between the first lens unit and the second lens unit increases and the separation between the second lens unit and the succeeding lens group decreases, and wherein the second lens unit includes a front lens subunit of negative refractive power and a rear lens subunit of negative refractive power disposed on the shorter conjugate side of the front lens subunit, focusing being formed by moving the rear lens subunit, and the following condition being satisfied:where fw and ft are focal lengths at the wide-angle end and the telephoto end of the zoom lens, respectively, and f2a is a focal length of the front lens subunit.
Inventors:
Makoto Misaka
Application Number:
JP20859498A
Publication Date:
January 20, 2010
Filing Date:
July 08, 1998
Export Citation:
Assignee:
Canon Inc
International Classes:
G02B15/20; G02B15/173
Domestic Patent References:
| JP10048518A | ||||
| JP2047617A | ||||
| JP2232613A |
Attorney, Agent or Firm:
Yukio Takanashi