| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens which is provided with five lens groups as a whole, where the refractive power of the respective lens groups and the movement conditions thereof associated with variable power are properly set, and which has high optical performance in all the variable power range and over the entire object distance, and to obtain optical equipment which uses the zoom lens. SOLUTION: This zoom lens is provided with five lens groups, that is, a 1st group having positive refractive power, a 2nd group having negative refractive power, a 3rd group having positive refractive power, a 4th group having positive refractive power and a 5th group having negative refractive power, in this order starting from the object side. In the case of varying power from a wide-angle end to a telephoto end, the respective lens groups are moved so that the interval between the 1st group and the 2nd group is increased, the space between the 2nd group and the 3rd group is decreased, the space between the 3rd group and the 4th group is increased, and the space between the 4th group and the 5th group is decreased; thus the lens constitution of the 3rd lens group is set appropriately.
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