| 摘要 |
A zoom lens system comprising, in order from an enlargement side, a first lens group of a negative power, a second lens group of a positive power and a third lens group of a positive power. The first lens group is fixed during a zooming operation from a longest focal length condition to a shortest local length condition and includes, in order from the enlargement side, a positive lens element, a negative lens element and an aperture stop. The second lens group includes two positive lens units which are movable independently of each other toward a reduction side during the zooming operation. The third lens group is also movable toward the reduction side during the zooming operation and includes, in order from the enlargement side, a positive lens element and a negative lens element.
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