| 摘要 |
A wide-angle zoom lens system includes a negative first lens group, a positive second lens group, a negative third lens group, and a positive fourth lens group. Upon zooming from the short focal length extremity to the long focal length extremity, the distance between the negative first lens group and the positive second lens group decreases, the distance between the positive second lens group and the negative third lens group increases, and the distance between the negative third lens group and the positive fourth lens group decreases; and the positive second lens group, the negative third lens group and the positive fourth lens group move toward the object. The wide-angle zoom lens system satisfies the following conditions: <?in-line-formulae description="In-line Formulae" end="lead"?>1.2<|f<SUB>(i=1)</SUB>/f<SUB>W</SUB>|<2.0 (1)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>1.5<f<SUB>(i=2)</SUB>/f<SUB>W</SUB><2.2 (2)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>2.5<|f<SUB>(i=3)</SUB>/f<SUB>W</SUB>|<3.6 (3)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>3.2<f<SUB>(i=4)</SUB>/f<SUB>W</SUB><4.7; (4)<?in-line-formulae description="In-line Formulae" end="tail"?> wherein fi designates the focal length (f 1 <0, f 3 <0) OF THE I<SUP>th </SUP>lens group (i=1~4); and f<SUB>W </SUB>designates the focal length of the entire the wide-angle zoom lens system at the short focal length extremity.
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