Patent ID: 8339575

Claim:
Objective, comprising: a plurality of optical elements that are arranged along a ray path, including at least one optical element of a first kind, which is irradiated only partially by a ray bundle, wherein the at least one optical element of the first kind is rotatably mounted or positioned about the optical axis or an axis parallel to the optical axis, wherein, for the optical element of the first kind, at least two mounting positions are provided, wherein the rotation angle between the two mounting positions is defined by the surface irradiated by the ray bundle such that, in the two mounting positions, the surfaces irradiated by the ray path do not overlap, wherein the at least one optical element is a lens or a mirror, wherein the at least one optical element includes areas which each correspond respectively to the mounting positions, which each cover the respective surfaces irradiated by a ray bundle, wherein the areas differ in design, and wherein the areas differ in at least one of filter characteristic, detuned coating, coating layer thickness, coating characteristic, birefringency, material, and crystal orientation.