发明名称 Zoom lens system and image pickup apparatus including the same
摘要 A zoom lens system, includes, in order from an object side to an image side: a positive first lens unit which does not move for zooming; a negative second lens unit which moves for zooming; a positive third lens unit which moves for zooming; and a fourth lens unit which does not move for zooming, is provided for imaging, and has a positive refractive power, in which the third lens unit includes multiple lenses including a positive lens and a negative lens, and the third lens unit satisfies:−2.0×10−3<(θpa−θna)/(νpa−νna)<−1.4×10−3; and 41<νpa−νna<53; and 2.9<SGa3<3.2, whereνna andθna indicate averages of Abbe number and partial dispersion ratio respectively, of the negative lenses,νpa andθpa indicate an average Abbe number of the positive lenses of the positive lenses included therein, respectively, and SGa3 indicates an average specific gravity of the lenses.
申请公布号 US8149518(B2) 申请公布日期 2012.04.03
申请号 US20100856988 申请日期 2010.08.16
申请人 NURISHI RYUJI;CANON KABUSHIKI KAISHA 发明人 NURISHI RYUJI
分类号 G02B15/14 主分类号 G02B15/14
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