| 摘要 |
A zoom lens includes a first movable lens group having negative power and a second movable lens group having positive power, and an immovable diaphragm provided between the first and second lens groups so as not to move during the zooming operation. The zoom lens satisfies (1) 0.45<fw/f2<0.7, (2) 0.5<f2/|f1|<1.0, and (3) 0.8<Dw/f2<1.3, whereby fw represents the focal length of the entire optical system at the wide-angle extremity, f1 represents the focal length of the first lens group (f1<0), f2 represents the focal length of the second lens group (f2>0), and Dw represents the distance between the diaphragm and the first principal point of the second lens group at the wide-angle extremity.
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