发明名称 Zoom lens system
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, in this order from the object; upon zooming from the short focal length extremity to the long focal length extremity, the first to the fourth lens groups move along the optical axis of the zoom lens system in a manner so that the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the distance between the third lens group and the fourth lens group increases; wherein the zoom lens system satisfies the following condition: 13.50<f1/fw<19.50  (1) wherein f1 designates the focal length of the positive first lens group; and fw designates the focal length of the entire zoom lens system at the short focal length extremity.
申请公布号 US7852567(B1) 申请公布日期 2010.12.14
申请号 US20100780008 申请日期 2010.05.14
申请人 HOYA CORPORATION 发明人 KANAZASHI YASUO
分类号 G02B15/14 主分类号 G02B15/14
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