| 摘要 |
PROBLEM TO BE SOLVED: To provide an image capturing optical system which reduces flare/ghost caused by a diffraction optical element as much as possible by reducing exposure of the diffraction optical element to high intensity light, such as sun light, from outside a screen, corrects well for chromatic aberration, and easily delivers high optical performance.SOLUTION: An image capturing optical system comprises, in order from the object side to the image side, a front group having a plurality of lenses, an aperture stop, and a rear group having a plurality of lenses, and also includes a diffraction optical element which is located on an optical path and has a diffraction optical surface having positive power. A distance Ldo-sto from the diffraction optical surface to the aperture stop along the optical axis, a grating pitch P(1) of a diffraction grating constituting the diffraction optical surface along the optical axis, a minimum grating pitch P(MIM) inside a light beam effective diameter on the diffraction optical surface, and a focal length f of the entire system when focused on an object at infinity are each set appropriately. |
