An image sensor including a pixel that includes: a first photoelectric conversion unit and a second photoelectric conversion unit, each of which generates an electric charge through photoelectric conversion of light; an output unit that outputs a first signal generated based upon the electric charge generated in the first photoelectric conversion unit and a second signal generated based upon an electric charge generated in the second photoelectric conversion unit; and an adjustment unit that adjusts a capacitance at the output unit upon outputting of the first signal and the second signal from the output unit.