1. An image capturing apparatus comprising: a computing unit which computes, from an image captured using an image sensor, an amount of blown-out highlights of the image; an enhancement amount determining unit which determines, based on a magnitude of the amount of blown-out highlights, an amount of dynamic range enhancement for lessening the amount of blown-out highlights; a correction amount determining unit which determines a lessoning amount of ISO speed that depends on the amount of dynamic range enhancement, and a correction amount for correcting a brightness of an image captured at the lessened ISO speed; a control unit which performs image capture using the image sensor, at the ISO speed determined by the correction amount determining means; and a correcting unit which corrects the brightness of an image captured by the control means, in accordance with the correction amount.