| 摘要 |
A three-group zoom lens has, from an object side, a first group lens having a positive power, a second group lens having a negative power and a third group lens consisting of a positive lens. The second lens group includes an aperture stop. When a distance to be focused is infinity, only the first lens group and the second lens group move for zooming. At least one positive lens included in the zoom lens has an aspherical surface whose positive power is greater at a portion farther from an optical axis thereof. The zoom lens satisfies the following conditions: <paragraph lvl="0"><in-line-formula>-0.85<f2/f1<-0.65 </in-line-formula>and <paragraph lvl="0"><in-line-formula>5.0<f3/fw<8.0 </in-line-formula>where, fw represents a focal length when positioned at a wide-extremity, and f1, f2 and f3 respectively represent focal lengths of the first, second and third lens groups.
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