| 摘要 |
A high zoom-ratio zoom lens system of five lens groups includes a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a negative fifth lens group, in this order from the object. Upon zooming from the short focal length extremity to the long focal length extremity, a distance between the first lens group and the second lens group increases, and a distance between the second lens group and the third lens group decreases. The high zoom-ratio zoom lens system satisfies the following conditions: 5.5f1/|f2|f2 1.7f3/f4 wherein f1 designates the focal length of the first lens group; f2 designates the focal length of the second lens group; f3 designates the focal length of the third lens group; and f4 designates the focal length of the fourth lens group.
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