A method for detecting an imaging quality of an optical system , comprising at least one lens or a lens group, with an apparatus comprising: an MTF measuring apparatus for measuring a modulation transfer function at a plurality of field points in the imaging field of the optical system , wherein the MTF measuring apparatus is configured to perform a plurality of off-axis MTF measurements, and - a centering measuring apparatus for measuring a centered state of the optical system that is arranged on-axis, wherein the centering measuring apparatus comprises an autocollimator and is configured to measure a center of curvature of at least one optical surface of the optical system in reflection, wherein - a centered state of the optical system is determined with the centering measuring apparatus , - the optical system is centered based on the data on the centered state, and then - a modulation transfer function of the optical system is performed by the MTF measuring apparatus at a plurality of field points in the field of view of the optical system , wherein after a centering process, (i) a modulation transfer function of the optical system is determined with the MTF measuring apparatus , (ii) then a position of an optical element is changed slightly and then a modulation transfer function of the optical system is again determined with the MTF measuring apparatus , wherein steps (i) and (ii) are repeated iteratively until the modulation transfer function reaches a local maximum value. an MTF measuring apparatus for measuring a modulation transfer function at a plurality of field points in the imaging field of the optical system , wherein the MTF measuring apparatus is configured to perform a plurality of off-axis MTF measurements, and - a centering measuring apparatus for measuring a centered state of the optical system that is arranged on-axis, wherein the centering measuring apparatus comprises an autocollimator and is configured to measure a center of curvature of at least one optical surface of the optical system in reflection, wherein - a centered state of the optical system is determined with the centering measuring apparatus , - the optical system is centered based on the data on the centered state, and then - a modulation transfer function of the optical system is performed by the MTF measuring apparatus at a plurality of field points in the field of view of the optical system , wherein - a centering measuring apparatus for measuring a centered state of the optical system that is arranged on-axis, wherein the centering measuring apparatus comprises an autocollimator and is configured to measure a center of curvature of at least one optical surface of the optical system in reflection, wherein - a centered state of the optical system is determined with the centering measuring apparatus , - the optical system is centered based on the data on the centered state, and then - a modulation transfer function of the optical system is performed by the MTF measuring apparatus at a plurality of field points in the field of view of the optical system , wherein after a centering process, (i) a modulation transfer function of the optical system is determined with the MTF measuring apparatus , (ii) then a position of an optical element is changed slightly and then a modulation transfer function of the optical system is again determined with the MTF measuring apparatus , wherein steps (i) and (ii) are repeated iteratively until the modulation transfer function reaches a local maximum value. <EOS>