| 摘要 |
A telephoto lens TL having, in order from an object, a plurality of lenses L1, L2, . . . and a diffractive optical element DOE which has a diffraction grating having a rotationally symmetric shape with respect to the optical axis, wherein the diffractive optical element DOE is disposed on any one of lens surfaces of the plurality of lenses L1, L2, . . . , and conditional expression 0.50<fa/Rd<0.90 or 1.10<fa/Rd<2.00 is satisfied, where fa denotes a combined focal length of each lens from the lens L1, which is closest to the object, of the plurality of lenses L1, L2, . . . to the lens L2, on which the diffractive optical element DOE is disposed, and Rd is a radius of curvature of the lens surface on which the diffractive optical element DOE is disposed.
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