Patent ID: 7554585

Claim:
An image sensing apparatus for interval photography, in which photography is repeatedly performed at predetermined time intervals, said image sensing apparatus comprising: an image sensing element which performs photoelectric conversion; a shutter which selectively creates a light-shielded state and non-light-shielded state for the image sensing element; a bright signal storage unit which stores a bright signal output from the image sensing element in the non-light-shielded state; a dark signal storage unit which stores a dark signal output from the image sensing element in the light-shielded state; an operation unit which subtracts the dark signal from the bright signal to obtain a signal with suppressed dark noise; and a control unit which controls reading the bright signal and dark signal from the image sensing element in accordance with a relationship between an exposure time of the image sensing element and a photographing time interval; wherein, if a photographing interval (T intvl ) and an exposure time (T exp ) of the image sensing element do not satisfy T intvl ≧2×T exp +α (where α represents a time margin), the control unit reads out a dark signal before starting repetitive photography, the readout dark signal is stored in the dark signal storage unit, and the operation unit subtracts the dark signal stored in the dark signal storage unit from each of bright signals read out by repetitive reading.