Image capturing apparatus which improves focus detection accuracy by using an image sensor having a pupil division function

Abstract

An image capturing apparatus comprises a pixel array in which a plurality of column output lines including a first column output line and a second column output line are arranged for each column; and a readout circuit configured to read out signals from the pixels via the column output lines, wherein the readout circuit performs a first read-out scan of reading out signals via the first column output line from a first pixel group of the pixel array, and a second read-out scan of reading out signals via the second column output line from a second pixel group, and the readout circuit reads out a phase-difference signal of a horizontal direction by the first read-out scan, and reads out a phase-difference signal of a vertical direction by the second read-out scan.