A device for beam adjustment in an optical beam path, having at least two mutually independent light sources providing respective beams of a high or extremely high resolution microscope, the beams of the light sources superposed in a common illumination beam path. The device includes a calibration sample with the aid of which the pupil position and/or focal position of the beams can be checked. The device also includes a sample holder arranged to bring the calibration sample into and out of the common illumination beam path at the site or in the vicinity of an intermediate image. A corresponding method is described. In accordance with the device and method, it is possible to undertake the beam adjustment independently of the actual use, that is to say, in the case of a high resolution microscope, independently of the examination sample and/or the recording of images.