| 摘要 |
PROBLEM TO BE SOLVED: To provide a photometric optical system having a deep depth of focus and less in color shift due to defocusing, and an imaging apparatus having the same.SOLUTION: A photometric optical system has at least one of lenses 6 including an aspheric surface and forms an object image in an image sensor 7. When the shape X of the aspheric surface is expressed by the following formula (1), and the second-order differentiation Z thereof is expressed by the following formula (2): X=h/{R[1+[1-(1+k) h/{R}]+A4h+A6h+A8h+A10h+..} (1); and dX/dh=Z (h) (2), and the following formulas (3) is satisfied with respect to the center diameter rk of the k-th area in the radial direction from the optical axis when the effective diameter of a lens surface in the lens is equally divided into ten in the radial direction from the optical axis; 1<|Z(rk)×rk|/10 (3), where 5<k<8. |
