Definition of field curvature in English:

field curvature

noun

Optics
  • Curvature of the focal surface of a lens or other optical system; (Photography) an aberration caused by the use of a lens with a curved focal surface in capturing an image on a flat surface, the edges of the image being out of focus when the centre is in focus (and vice versa).

Origin

Late 19th century; earliest use found in U.S. Patents.