| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens system which includes three lens groups, such as, in order from an object side, a first lens group with negative refractive power, a second group with positive refractive power, and a third lens group with positive refractive power, has a zoom ratio of approximately 3, corrects various aberrations suitably, and covers a range from the wide-angle extremity to the telephoto extremity. SOLUTION: In the zoom lens system, all of the first lens group, the second lens group and the third lens group are moved for zooming, the second lens group includes three lenses, which are a second-1 lens with positive refractive power, a second-2 lens with negative refractive power, and a second-3 lens with negative refractive power, in this order from the object, and conditional expressions: 2<f2/rb<3 (1) and 0.4<f2/f3<0.8 (2), wherein f2 is the focal length of the second lens group; rb is the radius of curvature of the image-side surface of the second-3 lens on the optical axis; and f3 is the focal length of the third lens group. COPYRIGHT: (C)2010,JPO&INPIT |
