Microscope, and method for modifying the light flux in a microscope

A microscope includes a light source, an illuminating optical system, an aperture device, and a spectral correction device. The light source includes a control device for controlling the intensity of light emitted by the light source. The illuminating optical system has a numerical aperture and illuminates a specimen. The aperture device is located in the illumination beam path and modifies the numerical aperture. The spectral correction device is located in the illumination beam path and corrects a change in the spectral intensity distribution of the light emitted by the light source so that the spectral intensity distribution of light directed onto the specimen remains substantially unchanged. Upon a change of the numerical aperture by the aperture device, the light source is controllable by the control device of the light source so that the light flux through the illuminating optical system remains substantially unchanged.