An image sensor: includes a pixel matrix in which pixels are disposed in a matrix, each pixel including a photoelectric conversion element and a switching element connected to the photoelectric conversion element; performs selection processing, on each pixel row of the pixel matrix, including selecting a pixel row and outputting a signal to the selected pixel row to make switching elements conductive; performs detection processing of detecting signals from the photoelectric conversion elements in the selected pixel row; and performs the selection processing based on received control signals, wherein the control signals include first control signals having a cycle shorter than a first period in which the selection processing and the detection processing are performed on all pixel rows, and wherein the cycle is equal to or shorter than a second period in which the selection processing and the detection processing are performed on one pixel row.