1. An image capturing apparatus comprising: an optical low-pass filter configured to separate one incident ray into multiple rays to form multiple point images; and an image sensor configured to photoelectrically convert the multiple point images, wherein the optical low-pass filter satisfies the following condition: 
 0.4<2×σ/P<0.9 where P represents a pixel pitch of the image sensor, and σ represents a standard deviation of a distribution of the multiple point images, and wherein the optical low-pass filter is configured to separate the one incident ray, when one of the separation directions thereof is defined as 0°, in each of four directions of 0°, 45°±10°, 90°±10°, and 135°±10°.