Abstract: A microscope is provided with a supplementary means for producing a light spot in the object plane of the microscope objective lens. The supplementary means comprises a light source from which a collimated light beam is derived, a focusing lens receiving the collimated beam and a coupling lens disposed between the first lens and the objective lens. The supplementary means has the following features: the focal point of the focusing lens is in the plane of the image of a specimen in the object plane as obtained through the objective lens and the coupling lens, the light beam fills the clear aperture of the objective lens without substantial light loss and the light source and the focusing lens may be moved together to displace the light spot within or away from the object plane of the objective lens.