An objective and an illumination unit for selectable generation of an orthoscopic beam path proceeding through the objective for pointlike scanning illumination, and of a conoscopic beam path proceeding through the objective for evanescent illumination of an object are disclosed. The illumination unit has a light source for generating illuminating rays along an illuminating beam path; a displacement unit for deflecting the illuminating beam path; a scanning eyepiece, placed after the displacement unit for focusing the illuminating rays into an image plane of the scanning eyepiece; and a mirror surface arranged in the image plane of the scanning eyepiece, having a transparent region for generating the orthoscopic beam path and having an at least partly reflective region facing toward the scanning eyepiece for generating the conoscopic beam path from the illuminating beam path, the image plane is located in a plane conjugated with the exit pupil.