发明名称 Zoom lens system
摘要 A zoom lens system includes a positive first lens group, a negative second lens group, and a positive third lens group. The second and third lens groups move to perform a zooming operation. The zoom lens system satisfies the relationships 0<logZ2/logZ<0.4; 0.25<d1-2/fW<0.55; and 3<L2-3/fW<4.6, wherein "Z2" designates the ratio defined by the lateral magnification of the second lens group at the longest focal length extremity to the lateral magnification of the second lens group at the shortest focal length extremity, "Z" represents the ratio defined by the longest focal length of the entire zoom lens system to the shortest focal length of the entire zoom lens system, "fW" represents the shortest focal length of the entire zoom lens system, "d1-2" represents the distance between the last lens surface of the first lens group and the first lens surface of the second lens group at the shortest focal length extremity, and "L2-3" represents the distance between the principal points of the second and third lens groups at the shortest focal length extremity.
申请公布号 US5912771(A) 申请公布日期 1999.06.15
申请号 US19970935894 申请日期 1997.09.23
申请人 ASAHI KOGAKU KOGYO KABUSHIKI KAISHA 发明人 OZAKI, HIROYASU;ITO, TAKAYUKI
分类号 G02B15/16;G02B15/173;(IPC1-7):G02B15/14 主分类号 G02B15/16
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