An image sensor includes a plurality of vertical CCDs; first HCCD receiving charge packets from even numbered vertical CCDs; and a second HCCD receiving charge packets from odd numbered vertical CCDs; wherein four charge packets are summed together from the first HCCD, and four charge packets are summed together in the second HCCD such that the summing process in the second HCCD begins one or two charge packets spatially after the first charge packet of the four charge packets summed in the first HCCD.