| 摘要 |
A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group. Upon zooming, each of the first through fourth lens groups independently move along the optical axis. The positive first lens group includes a negative first lens element and a positive second lens element, in this order from the object. The zoom lens system satisfies the following conditions:whereinn1-2 designates the refractive index of the positive lens element of the positive first lens group;DeltaX1 designates the traveling distance of the positive first lens group from the short focal length extremity to the long focal length extremity; andf designates the focal length of the entire zoom lens system at the short focal length extremity.
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