| 摘要 |
PROBLEM TO BE SOLVED: To provide a three-group zoom lens which is suitable to a compact camera and small-sized and has high power variation and a wide field angle and an imaging device equipped with the same. SOLUTION: The zoom lens comprises a 1st lens group G11 having positive refracting power, a 2nd lens group G12 having positive refracting power, and a 3rd lens group G13 having negative refracting power in order form an object side and varies the power from a short-focal-length end to a long-focal-length end by moving the respective lens groups toward the object side; and the 2nd lens group G2 has three lenses L13, L14, and L15 and the 3rd lens group G3 is constituted by L16 one simple lens and satisfies conditional inequalities as follows: 3.0<ft/fw, 0.7<IH/fw<0.9, 1.75<ft/fl_G1<2.5, and 2.8<fw/sk_w<4.1 (where ft is the focal length at the long-focal-length end; fw is the focal length at the short-focal-length end; IH is maximum image height; fl_G1 is the composite focal length of the 1st group; and sk_w is the back focus at the short-focal-length end). COPYRIGHT: (C)2005,JPO&NCIPI
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