An optical filter includes pixels, each including: a first reflective plate configured to receive light and having first holes; and a second reflective plate facing the first reflective plate, separated from the first reflective plate by a gap, and having second holes corresponding to the first holes in shape and orientation. The second reflective plate is configured to transmit the light of a wavelength or the light of a range of wavelengths transmitted through the first reflective plate and incident on the second reflective plate, according to a spacing between adjacent holes of the first holes or a spacing between adjacent holes of the second holes. At least one pixel has the spacing between adjacent holes of the first holes different from that of at least one another pixel, or has the spacing between adjacent holes of the second holes different from that of the at least one another pixel.