A digital camera (10a) is placed in any of three photographing modes labeled a “narrow mode”, a “normal mode”, and a “wide mode”. An operating point setter (903) variably sets an operating point of a CCD (26) defining a brightness range of a subject which falls within a dynamic range of an image sensor, based on a photographing mode as set. A LUT setter (902) variably sets a gradation correction LUT which is a concrete representation of gradation correction characteristics in gradation correction performed by a γ correction circuit (55) (characteristics in γ correction), based on the photographing mode as set. The operating point set by the operating point setter (903) and the gradation correction LUT set by the LUT setter (902) are changed in synchronism with each other in accordance with change in the photographing mode.