Patent ID: 6236516
Filing Date: 2001-05-22
Classification: G02B

Abstract:
A zoom lens comprising, 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 said first lens unit and said second lens unit increases and the separation between said second lens unit and said succeeding lens group decreases, and wherein said 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 said front lens subunit, focusing being performed by moving said rear lens subunit, and the following condition being satisfied:0.3<.vertline.f2a.vertline./(fw.times.ft)<0.9where fw and ft are focal lengths at the wide-angle end and the telephoto end of said zoom lens, respectively, and f2a is a focal length of said front lens subunit, andwherein said first lens unit moves during zooming.