1. An image capturing apparatus comprising: focal position adjusting means for adjusting a focal position of an optical system to a predetermined position in a first image capture period and adjusting so as to change the focal position of the optical system in a second image capture period; displaying means for displaying an image captured in the first image capture period; distribution generating means for generating a distribution of sharpness corresponding to focal positions based on an image captured in the second image capture period; and focused position detecting means for detecting the focal position of the optical system, at which an image of a subject is in focus, based on distribution of sharpness corresponding to focal positions generated by the distribution generating means.