| 摘要 |
PROBLEM TO BE SOLVED: To obtain a small-sized zoom lens where the moving amount of a focusing lens group is prevented from extremely increasing at the time of focusing by performing focusing by a 2nd lens group and making the 2nd lens group satisfy a specified condition. SOLUTION: This zoom lens is provided with a 1st lens group I having positive refractive power, a 2nd lens group II having negative refractive power and a following group constituted of plural or one lens group and being positive as a whole in order from a long conjugate side. In the case of performing variable power from a wide-angle end to a telephoto end, an interval between the 1st and the 2nd lens groups I and II gets large and an interval between the 2nd lens group II and the following group gets small. In the zoom lens, the 2nd lens group II is provided with a 2a-th group IIa having the negative refractive power and a 2b-th group IIb having the negative refractive power and arranged on a short conjugate side from the 2a-th group IIa, and focusing is performed by the 2b-th group IIb. When the magnification of the 2b-th group IIb at the wide-angle end is defined asβ2bw, a condition 0<β2bw<1 is satisfied.
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