1. An image sensor, comprising: a plurality of pixel units each of which includes a pixel and a reset transistor, wherein the pixel includes a photoelectric converting unit that performs photoelectric conversion on light of a certain color incident through a color filter and a transfer transistor that transfers charges obtained by the photoelectric conversion of the photoelectric converting unit and is controllable for each color, the reset transistor is connected to an analog to digital (AD) converting unit that performs AD conversion, and resets the charges, and according to control of the transfer transistor, the charges are read from the photoelectric converting unit through the transfer transistor and the reset transistor, and a voltage corresponding to the charges is supplied to the AD converting unit connected to the reset transistor.