| 摘要 |
A zoom lens system comprising, arranged sequentially from the enlarging side to the reducing side, a first lens group having a negative refractive power as a whole, a second lens group having a positive refractive power as a whole and a third lens group having a positive refractive power as a whole. The third group is fixed during the zooming. The first lens group moves along an optical axis from the enlarging side to the reducing side during zooming from the wide angle end to the intermediate area. The first lens group also moves along the optical axis from the reducing side to the enlarging side during zooming from the intermediate area to the telephoto end. The second lens group moves along the optical axis from the reducing side to the enlarging side during zooming from the wide angle end to the telephoto end. Thus, the zooming operation of the whole lens system is achieved.
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