| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens with less variation in distortion aberration on zooming, and having good optical performance. SOLUTION: The zoom lens includes in order from an object side to an image side: a first lens group of negative refractive power; a second lens group of positive refractive power; a third lens group of negative refractive power; and a fourth lens group of positive refractive power; wherein on zooming from a wide-angle end to a telephoto end, a distance between the first lens group and the second lens group is decreased. The first lens group includes a positive lens located closest to the object side, and the fourth lens group includes a negative lens located closest to the image side. The zoom lens satisfies conditional inequalities of 0.5<¾f1/f24¾<1.4, and 0.50<Rn/fw<15.0, where the focal length of the first lens group is denoted as f1, a composite focal length from the second lens group to the fourth lens group at the wide-angle end is denoted as f24, the focal length of the whole system at the wide-angle end is denoted as fw, the curvature radius of the image-side lens surface of the negative lens located closest to the image side in the fourth lens group is denoted as Rn. COPYRIGHT: (C)2010,JPO&INPIT
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