| 摘要 |
A compact zoom lens including three lens groups having positive, positive and negative refractive power, in order from the object side. The distance between the first and second lens groups, as well as the distance between the second and third lens groups, is decreased when zooming from the maximum wide angle state to the maximum telephoto state. Aberrations are made favorable, even when in the maximum wide-angle state, by satisfying prescribed conditional expressions as well as by specifying prescribed lens element shapes for the first lens group and the third lens group. By arranging a negative meniscus lens element at the front of the first lens group with its concave surface on the photographic object side, curvature of field and distortion, which otherwise become a problem when in the maximum wide-angle, are suppressed. By arranging, immediately behind the negative meniscus lens element, a positive meniscus lens with its convex surface on the photographic object side, the back-focus of the compact zoom lens can be held short. Furthermore, in the third lens group, by arranging a negative meniscus lens element at the extreme photographic object side, and by figuring each surface of this lens element to be aspheric, the usual deterioration in imaging performance which accompanies compactness can be effectively prevented. Further, a diaphragm stop 2 is arranged between the first lens group G1 and the second lens group G2.
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