1. An image capturing apparatus comprising: an optical system that provides an aberration to incident light; an image capturing unit that transforms the light passing through the optical system into pixels to capture an image; and an inverse transform unit that performs inverse transform processing on the image captured by the image capturing unit, wherein the inverse transform unit performs the inverse transform processing using an inverse transform filter that performs transform such that frequency characteristics of pixels in two or more of defocus positions, in an output image, within a predetermined range on an optical axis of the optical system, have a larger value in at least one defocus position with respect to frequency characteristic of pixels in an ideal image and have a smaller value in at least one other defocus position with respect to the frequency characteristic of the pixels in the ideal image.