The invention relates to an optical system for a microlithographic projection exposure apparatus, and to a microlithographic exposure method. An optical system for a microlithographic projection exposure apparatus comprises at least one mirror arrangement having a plurality of mirror elements, wherein these mirror elements can be adjusted independently of one another for changing an angular distribution of the light reflected by the mirror arrangement, and a polarization-influencing optical arrangement which is arranged downstream of the mirror arrangement in the light propagation direction, wherein the polarization-influencing optical arrangement reflects a light beam incident on the arrangement in at least two reflections, which do not occur in a common plane, for at least one angular distribution of the light reflected by the mirror arrangement.