| 摘要 |
The present invention provides a zoom lens system which has a fast f-number, and favorably corrects various aberrations so that a superior optical quality is achieved. The zoom lens system includes a positive first lens group, a negative second lens group, a third lens group which includes at least one positive lens element or one negative lens element, a positive fourth lens group, and a negative fifth lens group, in that order from the object side. At least the first lens group, the second lens group, the fourth lens group and the fifth lens group are moved during zooming from the short focal length extremity to the long focal length extremity, and the following conditions (1) and (2) are satisfied: ˆ’ 6.5 < f 1 / f 5 < ˆ’ 4.6 and ˆ’ 1.2 < fw / f 3 < 0.7 wherein
f1 designates the focal length of the first lens group,
f3 designates the focal length of the third lens group,
f5 designates the focal length of the fifth lens group, and
fw designates the focal length of the entire zoom lens system at the short focal length extremity. |
