Described is an examination system (1) for locating contamination (2) on an optical element (4) installed in an optical system (5), which examination system (1) comprises: a spatially resolving detector (6); imaging optics (7) that magnify in particular at a magnification of between 2 times and 100 times, for magnified imaging of a surface sub-region (3a) of the optical element (4) on the spatially resolving detector (6); as well as a movement mechanism (12), in particular a motorized movement mechanism (12), for displacing the imaging optics (7) together with the detector (6) relative to the surface (3) of the optical element (4) such that any desired surface sub-region of the surface (3) can be imaged at magnification.