| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens composed of 3 groups of lenses which is suitable for an electronic still camera with a shortened overall length of lens which is conveniently carried, and to obtain an optical device having the zoom lens. SOLUTION: In the zoom lens which has a first lens group having a negative refractive power, a diaphragm, a second lens group having a positive refractive power, and a third lens group having a positive refractive power in the order from an object, and the distance between the first and the second lens groups varies during zooming, the second lens group has an independent positive lens and an negative lens in order from the object, and the conditions 0.2<d23W/fw<1.0 and 0.2<d23T/fw<1.0 are satisfied, where d23W and d23T stand for the distances between the second lens group and the third lens group at the wide angle end and the telescopic end, respectively, when the lens is focused at infinity, and fw stands for the focal length of the whole system at the wide angle end. COPYRIGHT: (C)2004,JPO
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