| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens where aberration is excellently corrected by the small number of lenses by changing an interval between a negative lens group and a positive lens group at the time of variable power. SOLUTION: A second positive lens group G3 including two groups of the negative lens group G1 and the positive lens group G2 in order from the side of an object and including an optical element having a surface DOE where at least one surface has diffracting action nearly rotationally symmetrically with respect to an optical axis on the side of an image from the first positive lens group G2 is arranged, and at least the interval between the negative lens group G1 and the positive lens group G2 is changed at the time of the variable power. In this case, it is desirable to satisfy the conditional expression of 0.02<=f3 /ν2 f2 )<=0.4 and -25<=ν1 -ν2 <=20 so as to excellently correct chromatic aberration. In the expression, f2 means the focal distance of the first positive lens group G2, and f3 means the focal distance of the surface having the diffracting action,ν1 means the equivalent Abbe number of the negative lens group G1 andν2 means the equivalent Abbe number of the first positive lens group G2.
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