| 摘要 |
A zoom lens system includes a positive first lens group, a positive second lens group, a diaphragm, and a negative third lens group. The first through third lens groups move in an optical axis direction for zooming. The positive first lens group includes a negative lens element, and at least one positive lens element. The negative lens element is positioned at the most object-side of the positive first lens group, and is provided with a concave surface on the object-side surface thereof. The zoom lens system satisfies the following conditions:<paragraph lvl="0"><in-line-formula>-1.0<r1/fW<-0.5 (1);</in-line-formula><paragraph lvl="0"><in-line-formula>45<nup-nun (2);</in-line-formula><paragraph lvl="0"><in-line-formula>0.05<LD2/fT<0.09 (3);</in-line-formula>wherein r1: the radius of curvature of the object-side surface of the most object-side negative lens element in the positive first lens group; fW: the focal length of the entire zoom lens system at the short focal length extremity; fT: the focal length of the entire zoom lens system at the long focal length extremity; nup: the average Abbe number with respect to the d-line of the positive lens element in the positive first lens group; nun: the average Abbe number of the negative lens element in the positive first lens group; and LD2: the distance, along the optical axis in the positive second lens group, from the most object-side surface thereof to the most image-side surface thereof.
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