Prior to a photographing operation, an image blur quantity indicating the extent to which the image becomes blurred during the photographing operation is calculated based upon an image-capturing sensitivity having been set, and a decision is made as to whether or not the image-capturing sensitivity needs to be adjusted based upon the calculated image blur quantity. If it is decided that the sensitivity level needs to be adjusted, the image-capturing sensitivity is adjusted and the photographing operation is executed at the shutter speed calculated based upon the adjusted image-capturing sensitivity.