| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized light-weight high performance zoom lens at the small number of lenses. SOLUTION: The zoom lens has a negative first group G1, a positive second group G2 and a positive third group from an object side. When the focal distance is changed from a wide angle end to a telephoto end, an interval between the first group G1 and the second group G2 changes, an interval between the second group G2 and the third group G3 increases, and focusing is performed in the third group G3. The first group G1 is composed of a negative meniscus lens L11, directing a convex face to the object side, in which at least one lens face from the object side is aspheric and a positive lens L12 directing a convex face to the object side. The second group G2 is composed of a positive lens L21, directing a convex face to the object side, in which a diaphragm S and at least one lens face from the object side are aspheric, a joint lens of a positive lens L22 directing a convex face to the object side and a negative lens L23 directing a concave face to an image face side, and both convex positive lens L24. The third group is composed of a single positive lens L31, and they satisfy prescribed conditional equations. COPYRIGHT: (C)2005,JPO&NCIPI
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