An imaging operation includes a first imaging operation for outputting image data according to irradiation to the detector with radiation or light in an irradiation field A corresponding to a part of the plurality of pixels, and a second imaging operation for outputting image data according to irradiation to the detector 104 with radiation or light in an irradiation field B wider than the irradiation field A, wherein, responsive to a changing from irradiation in the irradiation field A to irradiation in the irradiation field B, an operation of the detector is controlled so that the detector performs an initializing operation for initializing conversion elements during a period between the first and second imaging operations.
