A light sensor is described with correlated double sampling. In one example a first storage element is coupled to a photodetector to collect free electrons as an accumulated charge. A transfer switch is coupled to the first storage element. A second storage element is coupled to the first storage element through the transfer switch to collect the accumulated charge from the first storage element when the transfer switch is open. A sense circuit measures the charge on the second storage element before the accumulated charge is collected from the first storage element as a reference charge and measures the charge on the second storage element after the accumulated charge is collected from the first storage element as a read charge. The sensed charge is determined by comparing the reference charge to the read charge.