| 摘要 |
The ZOOM LENS SYSTEM is provided to realize 2 at the short focal length extremity approximately by using negative first lens group, a positive second lens group and a positive third lens group. A zoom lens system includes in sequence from an object three groups, such as the first negative lens group(10), the second positive lens group(20), and the third positive lens group(30). For zoom working from short focus distance stage to long focus distance stage, all of the first negative group(10), the second positive lens group(20) and the third positive lens group(30) are arranged to move toward the direction of an optic axis. The first negative lens group mentioned above(10) includes in sequence from an object a negative lens element, a negative lens element and a positive lens element. The second positive lens group mentioned above(20) includes in sequence from an object a positive lens element, a positive lens element, a negative lens element and a positive lens element. The zoom lens system satisfies the following condition: 1.2 < f1G/f2G < 1.5. In the condition, f1G refers to the focus distance of the first negative lens group(fG<0), and f2G refers to the focus distance of the second positive lens group.
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