| 摘要 |
In a zoom lens having a variable power ratio representing a ratio of a focal length at a telephoto end position to a focal length at a wide angle end position being not less than 2.5 times, the zoom lens includes, in the order named from an object side: a first lens group having a negative focal length; a second lens group having an aperture-stop and a positive focal length; and a third lens group having a positive focal length. When a magnification is varied from the wide angle end position to the telephoto end position, all of the first, second and third lens groups are moved in an optical axis direction of the zoom lens so that a distance between the first and second lens groups is decreased. The first lens group Includes, in the order named from the object side, a first positive lens whose convex surface faces the object side, a second negative meniscus lens whose convex surface faces the object side, a third negative lens, and a fourth positive lens.
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