1. An image processing apparatus comprising: a first acquisition section configured to acquire a capturing parameter and a capturing image obtained by an image capturing device which uses the capturing parameter; a holding unit configured to hold a plurality of correction data in accordance with noise amounts; and a second acquisition section configured to acquire, corresponding to (a) an optical transfer function of the image capturing device derived from the capturing parameter and (b) an ISO sensitivity included in the capturing parameter, correction data among the plurality of correction data to correct a blur of the capturing image.