The present technology relates to an image sensor and a control method for an image sensor which are capable of measuring illuminance of each color in an image sensor. Each of a plurality of pixel units includes a pixel and a reset transistor, and 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. 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 an AD converting unit connected to the reset transistor. The present technology can be applied to, for example, an image sensor that photographs an image.