Microscope for observing a sample by means of various contrast methods

The invention relates to a microscope for observing a sample (13), preferably a biological substance, using various contrast methods, comprising a microscope stand (1) and extending a least partially inside the microscope stand (1) the illumination beam path with optical elements for forming an on the sample (13) directed beam (11). According to the invention, the microscope is equipped with a means for temporarily introducing a segment aperture (14) having a peripheral to the optical axis (15) of the illumination beam path disposed aperture (16) in the inside of the microscope stand (1) extending section of the illumination beam path.