| 摘要 |
The invention relates to a zoom lens that can achieve higher performance easily. In order from the object side of the zoom lens, it comprises a positive first lens group G1, a negative second lens group G2, a positive third lens group G3 and a positive fourth lens group G4, wherein zooming is implemented by a change in the space between the respective lens groups. Upon zooming from the wide-angle end to the telephoto end, while the space between the first lens group G1 and the second lens group G2 grows wide, the space between the second lens group G2 and the third lens group G3 becomes narrow and the space between the third lens group G3 and the fourth lens group G4 becomes narrow, the first, the third, and the fourth lens group moves toward the object side only, and the second lens group G2 moves in a convex orbit toward the image plane side. The second lens group G2, and the fourth lens group G4 has at least one aspheric surface, and the zoom lens satisfies the following conditions: 0.1<|f2/f1|<0.14 and 0.1<|f4/f3|<0.6 where fi is the focal length of an i-th lens group.
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