| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens having high resolution with a large aperture and high variable power. SOLUTION: This zoom lens is provided with the first lens group having a negative lens; a positive lens and a positive lens, in this order, starting from the object side, the second lens group having a negative lens, a negative lens, a positive lens and a negative lens, in this order, starting from the object side, the third lens group having a positive lens, a positive lens and a negative lens, in this order, starting from the object side, and the fourth lens group having one positive lens provided with one or more of aspheric faces, and satisfies conditional expressions: 0.3<¾f2/(fw×ft)<SP>1/2</SP>¾<0.50, 0.7<1-(βmax)<SP>2</SP><0.95 and 75.0<ν1, where f2 represents the focal distance of the second lens group, fw represents the focal distance in a wide-angle edge, fw represents the focal distance in a telescopic end,βmax represents the maximum value of transverse magnification, after the focus group between the wide angle edge and the telescopic end of the zoom lens, andν1 represents the Abbe's number for at least one positive lens, constituting the first lens group. COPYRIGHT: (C)2009,JPO&INPIT
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