petzval field curvature

Not to be confused with Petzval field curvature, which refers to focus uniformity.

Due to Petzval field curvature, the film plane upon which a lens focuses may not be a literal plane.

Field flattener lenses counteract the Petzval field curvature of an optical system.

The Petzval field curvature means that the image instead of lying in a plane actually lies on a curved surface which is described as hollow or round.

While astigmatism remains present in the Wright camera, it combines with the mirror's Petzval field curvature to result in a flat best image surface.

In this design, the sum of all the curvatures times indices of refraction can be zero, so that the field of focus is flat (zero Petzval field curvature).

Petzval field curvature, named for Joseph Petzval, describes the optical aberration in which a flat object normal to the optical axis (or a non-flat object past the hyperfocal distance) cannot be brought into focus on a flat image plane.