| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens system having a variable power ratio as high as about 6 times and excellent in cost performance and in environmental resistance though it is a negative lens group preceding type (so-called negative lead type) lens configuration. <P>SOLUTION: A zoom lens system is composed of a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power, in order from an object side. When varying power from the short to long focal length extremities, the first through third lens groups move along an optical axis direction so that the distance between the first and second lens groups decreases, and the distance between the second and third lens groups increases. The first lens group includes a glass lens having negative refractive power and at least two plastic lenses, in order from the object side, and in which the following condition (1) is satisfied: ¾f1/f1pc¾<0.04 (1), where f1 designates the focal length of the first lens group, and f1pc designates the combined focal length of the plastic lenses which are provided within the first lens group. <P>COPYRIGHT: (C)2012,JPO&INPIT |
