DIN 58172-1:2007-07

The standard applies to testing optical systems for the influence of deviations from symmetry on imaging quality. Deviations from symmetry are due to centring errors, unsymmetrical surface from errors or non-rotational inhomogeneities of the material used, or result from the mounting. The standard is not applicable to systems that are designed to have different properties in two perpendicular meridians, e. g. anamorphic systems.