| 摘要 |
PROBLEM TO BE SOLVED: To provide a small zoom lens which comprises a small number of lenses at a low cost and has high performance. SOLUTION: Relating to a zoom lens composed, in order from the object side, of a first group Gr1 having a negative power and a second group Gr2 having a positive power and performing power variation by changing the interval between the respective groups, in at least one group among two groups Gr1, Gr2, at least one surface of diffraction optical surface represented by a phase function by the following equation is provided.ϕ(H)=2π(ΣRf1 H<1> )/λ0 , where,ϕ: phase function, H: the height in the direction perpendicular to the optical axis, R1 : a first order phase coefficient,λ0 : a designed wavelength.
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