A method and apparatus for driving a solid state image pickup device. The method and apparatus include setting a first signal charging period and a second signal charging period for each one of a plurality of unit pixels. The second signal charging period is shorter than the first signal charging period. A first signal charge is produced during the first signal charging period and a second signal charge is produced during the second signal charging period. It is judged whether the first signal charge is saturated or not saturated. Then based on this judgment an input light amount is determined. The input light amount is determined using only the second signal charge when the first signal charge is saturated. The input light amount is determined using only the first signal charge when the first signal charge is not saturated.