FOCUS DETECTOR, CONTROL METHOD THEREOF, PROGRAM, AND MEMORY MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a focus detector capable of improving accuracy in focus detection of a phase difference detection method in which an output of an imaging device is used, and a control method of the focus detector.SOLUTION: The focus detector has: a first calculation part that detects a first phase difference between a first image signal based on a luminous flux passing through a part of region of an exit pupil of a photographic optical system, and a third image signal based on the luminous flux passing through a whole region of the exit pupil; a second calculation part that calculates a second phase difference between a second image signal based on the luminous flux passing through another part of region different from the part of the exit pupil, and a fourth image signal based on the luminous flux passing through the whole region of the exit pupil; and a defocus amount calculation part that calculates a defocus amount of the photographic optical system by using a sum obtained by multiplying the first phase difference and the second phase difference by weighting factors and adding the phase differences together.SELECTED DRAWING: Figure 12