1. An image sensor comprising: a semiconductor layer having a first surface and a second surface, the first surface being a light receiving surface; a first pixel that includes a first photoelectric conversion region formed in the semiconductor layer and a color filter formed over the light receiving surface, a signal from the first photoelectric conversion region being for an image capturing; a second pixel that includes a second photoelectric conversion region formed in the semiconductor layer and a light shield formed over the light receiving surface that blocks a part of light entering into the second pixel, a signal from the second photoelectric conversion region being for a focus detection; and a wiring layer formed over the second surface that includes wirings for transmitting signals from the first photoelectric conversion region and the second photoelectric conversion region.