Anastigmat

For the astigmatism correction of electron beams see Stigmator.

An anastigmat or anastigmatic lens is a photographic lens completely corrected for spherical aberration, coma, and astigmatism. Early lenses often included the word Anastigmat in their name to advertise this new feature (Doppel-Anastigmat, Voigtländer Anastigmat Skopar, etc.). All modern photographic lenses are close to being anastigmatic.