| 摘要 |
PROBLEM TO BE SOLVED: To provide a small zoom lens which is used for imaging equipment such as a cellular phone, a portable terminal, and an electronic still camera, the zoom lens in which priority is given to small size while having satisfactory image forming performance, distortion aberration characteristics, a sufficient quantity of peripheral light, a suitable back focus, and an exit pupil position extended as long as possible. SOLUTION: The zoom lens is a two-group zoom lens including, in order from object side, a first group that is negative and a second group that is positive, and varies a magnification by changing an interval between the two groups. The first group has, in order from object side, a first lens that is negative, and the second group has a second lens that is positive, an opening diaphragm, a third lens that is negative, and a fourth lens that is positive. The zoom lens satisfies the following conditional expression: (1) 2.2<TLw/fw<3.4 and (2) 0.9<fw/f2-4<1.3, wherein TLw denotes a length from a first lens face to the image forming face at a wide angle edge (air length conversion is used for a parallel flat section), fw denotes the focal distance of the entire lens system at the wide angle edge, and f2-4 denotes the focal distance of the second group. COPYRIGHT: (C)2006,JPO&NCIPI
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