A CCD image sensor includes vertical CCD shift registers and gate electrodes disposed over the vertical CCD shift registers. The gate electrodes are divided into distinct groups of gate electrodes. The CCD image sensor is adapted to operate in an accumulation mode and a charge transfer mode, an accumulation mode and a charge shifting mode, or an accumulation mode, a charge transfer mode, and a charge shifting mode. The charge transfer mode has an initial charge transfer phase and a final charge transfer phase. The charge shifting mode has an initial charge shifting phase and a final charge shifting phase.