| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens system being compact while having a variable power ratio of about 2.9 times, capable of achieving a reduction in the size of a focusing mechanism system and quick focusing, and satisfactory correcting spherical aberration and distortion aberration in focusing at a wide angle end, and to provide an optical device using the same. <P>SOLUTION: The zoom lens system comprises, in order from the object side: a negative first lens group; a positive second lens group which is a focus lens group moving during focusing; and a positive third lens group, and satisfies the following conditional expressions (1) and (2): (1) 0.4<¾d12w/f1¾<1.0, and (2) d12w<d23w, where f1 is a focal distance of the first lens group, d12w is an air interval between the surface closest to the image side in the first lens group and the surface closest to the object side in the second lens group at the wide angle end, and d23w is an air interval between the surface closest to the image side in the second lens group and the surface closest to the object side in the third lens group at the wide angle end. <P>COPYRIGHT: (C)2013,JPO&INPIT |
