| 摘要 |
A zoom lens system includes a positive first lens group, a negative second lens group. Zooming is performed by moving the first and second lens groups in the optical axis direction thereof. The most image-side lens element of the positive first lens group includes a positive lens element having at least one aspherical surface. The zoom lens system satisfies the following conditions: <?in-line-formulae description="In-line Formulae" end="lead"?>4.5<F<SUB>T</SUB>/f<SUB>1G</SUB><5.5 (1)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>3.5<F<SUB>T</SUB>/f<SUB>Lasp</SUB><5.5 (2)<?in-line-formulae description="In-line Formulae" end="tail"?> wherein f<SUB>T </SUB>designates the focal length of the zoom lens system at the long focal length extremity; f<SUB>1G </SUB>designates the focal length of the positive first lens group; and f<SUB>Lasp </SUB>designates the focal length of the positive lens element having the aspherical surface in the positive first lens group.
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