Image pickup and focus detection by calculating correlation of paired images

摘要

An image pickup apparatus has an image sensor (100, figure 1) with pixels for photoelectrical conversion of paired object images respectively formed by light fluxes passing through different areas of an exit pupil of an image capturing optical system 1301. Signal producing means 1306 produces paired image signals corresponding to respective paired object images for each of a plurality of pixel lines by using output from each of pixel lines included in a focus detection area (602, figure 6a) of the image sensor. Each pixel line has pixels arranged in a line in a first direction, and the pixel lines are arranged in rows in a second direction orthogonal to the first direction. The image pick up apparatus includes calculating means 1309 for calculating a defocus amount of the image capturing optical system by using the paired image signals produced for each pixel line. The calculating means is configured to for each pixel line, produce first correlation data by relatively shifting the paired image signals in the first direction and calculating a correlation value for each relative shift amount, add together corresponding correlation values of the first correlation data.