| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens whose zoom ratio is >=2.5, which has a viewing angle of >=60 deg. in a wide-angle end state and which has excellent image-formation performance by specifying constitution of the lens. SOLUTION: The constitution of this lens satisfies six following conditional expressions: 0.7<f2/|f1|<1.5(f1<0), 3<f3/fw<10, 1<f12/|f1|<3(f1<0), 1<|f22|/f2<5(f22<0), 1.6<(D1w-D1t)/fw<6 and 1.6<(D2t-D2w)/fw<6. In the expressions, f1 to f3 mean the focal lengths of 1st to 3rd lens groups G1 to G3, fw means the focal length of the zoom lens in the wide-angle end state. Then, f12 and f22 mean the focal lengths of (1-2)th and (2-2)th lens units. D1w and D1t mean air distances between G1 and G2 in the wide-angle end state and a telephoto end state, and D2w and D2t mean the air distance between G2 and G3 in the wide-angle end state and the telephoto end state.
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