| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens system which is made small-sized and has an excellent imaging quality. <P>SOLUTION: In the zoom lens system, a first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, a fourth lens group having a positive refracting power, and an imaging surface are arranged in this order from the object side to the image side. The first lens group and the third lens group are fixed not to move along an optical axis direction during zooming operation, and the second lens group and the fourth lens group are movable along the optical axis direction to move along the optical axis direction during zooming operation. The zoom lens system satisfies 5<f3/f4<8.2 and 2.1<¾f2/fw¾<3.2 where f2 is an effective focal length of the second lens group, f3 is an effective focal length of the third lens group, f4 is an effective focal length of the fourth lens group, and fw is an effective focal length of the zoom lens system in a wide-angle state. <P>COPYRIGHT: (C)2012,JPO&INPIT |
