| 摘要 |
PROBLEM TO BE SOLVED: To obtain a wide angle zoom lens system of a small size which prevents increasing of a lens diameter likely to increase with an increase in an angle of view even if the angle of view at a short focal length end is as wide as about 100°. SOLUTION: The wide angle zoom lens system consists of, successively from an object side, negative, positive, and positive three lens groups and moves so as to narrow both of the spacing between the first and second lens groups and the spacing between the second and third lens groups in zooming from the short focal length end to a long focal length end. The negative first lens group includes at least one positive lens and satisfies the following conditional expressions (1) and (2): (1) 0.30<fw/f<SB>1p</SB><0.40, (2) -1.0<(r<SB>1p-2</SB>+r<SB>1p-1</SB>)/(r<SB>1p-2</SB>-r<SB>1p-1</SB>)<1.0, where fw: the focal length of the entire system at the short focal length end, f<SB>1p</SB>: the focal length of the positive lens having the largest power in the first lens group, r<SB>1p-1</SB>: the radius of curvature of the surface of the positive lens on the object side having the largest power in the first lens group, and r<SB>1p-2</SB>: the radius of curvature of the surface of the same positive lens on the image side. COPYRIGHT: (C)2004,JPO
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