An image sensor that captures an image of light from a predetermined depth of a subject, includes: a photoelectric converter that photoelectrically converts light including interference light of light from the subject and reference light; a discrimination unit that locks in and detects a signal component having an interference frequency in an interference light component corresponding to the predetermined depth from a signal output from the photoelectric converter; and a floating diffusion unit that temporarily accumulates an electric charge resulting from the photoelectric conversion by the photoelectric converter; wherein: the discrimination unit includes: a transfer unit that transfers the signal to the floating diffusion unit; and a sampling unit that samples the electric charge accumulated in the floating diffusion unit at a sampling frequency determined based on the interference frequency.