| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens which comprises three groups having positive, positive, and negative power respectively, is small in the ratio of a distance FV from the most object-side lens surface at the telephoto end to a focal plane and a composite focal length ft at the telephoto end, and has various aberrations corrected satisfactorily. SOLUTION: A first lens group G1 most on the object side is composed of two lenses, i.e., a negative lens L11 and a positive lens L12 and the powers of the first and second lens groups are so set that conditions (1) and (2) are satisfied. Consequently, the three-group zoom lens can be provided which is very compact, or has a 0.8 or smaller ratio of the distance FV and focal length ft and has very satisfactory image forming performance. Here, (1) 1.6<f1/fw<2.0 and (2) 0.6<f2/fw<0.8, where respectively f1 is the focal length of the 1st lens group, fw the focal length of the zoom lens at the wide-angle end, and f2 the focal length of the 2nd lens group.
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