In a digital camera using an image pickup device such as CCD, a high
resolution and properly exposed image is obtained by composition a
plurality of image data of the same object taken by a plurality of image
pickup operation when a luminance of the object is lower. Each image data
is taken under a condition that an integration time (a charge storage
time) of the image pickup device is shorter than a limit integration time
causing a camera shake. A position of a frame on the image pickup device
from which electric charges of the pixels are read out as the image data
is corrected so as to cancel the movement of the camera between the image
pickup operations.