FOCUS DETECTION OPTICAL SYSTEM

摘要

PROBLEM TO BE SOLVED: To obtain a focus detection optical system in which a focus detection error caused by a difference in a color temperature of a light source is sufficiently small.SOLUTION: The focus detection optical system comprises: a condenser lens 10 that is disposed behind an expected imaging surface of an imaging lens; a separator mask 30 that is disposed behind the condenser lens 10 and includes at least a pair of apertures; a separator lens 40 that is disposed behind the separator mask 30 and includes at least a pair of lenses facing at least a pair of apertures of the separator 30; and a photoelectric conversion element 50 that is disposed behind the separator lens 40. In the focus detection optical system of a phase difference detection method causing a subject image on the expected imaging surface of the imaging lens to be once again formed on a sensor area of the photoelectric conversion element 50, a diffraction chromatic aberration correction element 60 is provided that has a diffraction surface positioned in front of or behind the separator mask 30 and formed into a symmetry shape with respect to an optical axis of the condenser lens 10.