| 摘要 |
A zoom lens system is composed of a first lens group of a positive power, a second lens group of a negative power, a third lens group of a positive power, and a fourth lens groups of a positive power arranged in this order from the object side, the magnification of said zoom lens system being changed by moving the second and third lens groups relative to each other and to the first and fourth lens groups while the positions of the first and fourth lens groups are fixed, wherein focal lengths of the first to fourth lens groups are defined to satisfy the following conditions:100<f1/fw<5002.3<|f2|/fw<3.51<f4/f3<2wherein f1, f2, f3 and f4 are the focal lengths of the first to fourth lens groups, respectively; and fw is the focal length of the zoom lens system in a wide-angle terminal.
|
