| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens the back focus of which is comparatively short and which has excellent optical performance and variable power ratio of about 3-4, and to obtain an optical apparatus using the same. SOLUTION: This zoom lens has a first group L1 having negative refracting power, a second group L2 having positive refracting power, a third group L3 having the positive refracting power and a fourth group L4 having the negative refracting power, arranged in this order from an object side. Variable power from a wide angle end to a telephoto end is performed by moving each lens group so that an axial gap between the first and second groups and the axial gap between the second and third groups are increased but the axial gap between the third and fourth groups is reduced. At least one diffraction optical element is provided for at least one lens group.
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