| 摘要 |
<P>PROBLEM TO BE SOLVED: To have a half field angle at a wide-angle end of 38° or more and a variable power ratio of substantially 3 times, have a resolution power corresponding to an image pickup device with 10 to 15 million pixels despite a compact size, and achieve a fast focusing. <P>SOLUTION: A zoom lens, in order from an object side, includes: a positive first lens group G1; a negative second lens group G2; a negative third lens group G3; and a positive fourth lens group G4. The third lens group G3 comprises a single negative lens, and the fourth lens group G4 has an aperture stop S in the object side. When varying power from a wide-angle end to a telephoto end, the respective groups are moved such that a gap between the first lens group G1 and the second lens group G2 and a gap between the second lens group G2 and the third lens group G3 increase respectively, and a gap between the third lens group G3 and the fourth lens group G4 decreases. In focusing, the third lens group G3 moves. A value obtained by dividing an air gap between the third lens group G3 at the wide-angle end and the aperture stop AD, by a focal length of the telephoto end falls within a predetermined range. <P>COPYRIGHT: (C)2013,JPO&INPIT |
