| 摘要 |
PROBLEM TO BE SOLVED: To provide a three-group zoom lens of a rear focus type which maintains a good performance from infinity to a short distance. SOLUTION: The zoom lens has a first lens group G1 having negative power, a second lens group G2 having positive power including a diaphragm and a third lens group G3 which is a lens for focusing and has positive power in order from an object side. When performing variable power from a wide end to a tele end when infinite distance focusing, only the first lens group and the second lens group are moved, and at least one plane of a positive lens has an aspherical surface on which positive power becomes large toward peripheries from an optical axis by composing the third lens group of one positive lens.
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