| 摘要 |
PROBLEM TO BE SOLVED: To reduce ghost images caused by the lens surface reflection between the first and second lens groups provided at the object side of the aperture diaphragm in a zoom lens. SOLUTION: This zoom lens has a first positive lens group, a second negative lens group, succeeding lens groups positive as a whole, and an aperture diaphragm between the second and third lens groups. When changing the magnification from the wide angle to the telescope, it increases the distance between the first and second lens groups and decreases the distance between the second lens group and the succeeding lens groups. Representing the curvature radiuses of the i-th and (i+1)th lens surfaces from the object side in the lens configuration of the first and second lens groups by r<SB>i</SB>and r<SB>i+1</SB>, it has lens surfaces S<SB>i</SB>and S<SB>i+1</SB>satisfying condition (1) 1.0<r<SB>i</SB>/r<SB>i+1</SB><5.0. Further, it applies reflectivity reduction processing to the lens surfaces forming at least a pair of the lens surfaces satisfying condition (1) for reducing the intensity of the ghost images. COPYRIGHT: (C)2007,JPO&INPIT
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