An image sensor with a simple configuration that generates an image to which a filter has been applied is disclosed. An image sensor comprises a plurality of pixels, each pixel including a photoelectric converter that detects incidence of single photons; and a counter that counts pulses present in an output signal from the photoelectric converter. The image sensor outputs a count value as a pixel value, wherein the count value is obtained by counting the pulses present in the output signals from a plurality of the photoelectric converters in a first period, or by counting the pulses present in the output signal from a single photoelectric converter in the first period and a second period.