| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens having a substantially compact focus group, having a small moving amount of the focus group, being compact, having a high performance, a half-angle end of a wide field angle of 36.8° or more, a variable-power ratio of 3 times to 5 times, and a resolution adapted to an image pickup element with 5,000,000-10,000,000 pixels. <P>SOLUTION: The zoom lens is disposed with in order from an object side to an image side along an optical axis: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a negative refractive power; and a subsequent group comprising a plurality of or a single lens group. The focusing is performed by the third lens group. A focal length of the second lens group, a focal length of the third lens group, a composite focal length of the second lens group and the third lens group at the telephoto end, and an intermediate focal length between a focal length of the entire system at the wide-angle end and a focal length of the entire system at the telephoto end satisfy predetermined conditional expressions. <P>COPYRIGHT: (C)2012,JPO&INPIT |
