In microscopes, particularly laser scanning microscopes, for detecting light coming from a sample, it is known to protect detectors from excessively high light outputs by means of shutters in the detection beam path. Further, in order to measure the light output impinging on the detector when the detection beam path is closed, a portion of the light is coupled out of the detection beam path and directed to a monitor diode. Constructions of this kind are complicated and costly. In the microscope according to the invention, a monitor diode is arranged on the shutter in such a way that the monitor diode is situated in the detection beam path when the shutter is closed. This makes it possible in a simple manner to measure the light output in a microscope when the detection beam path is closed even without additionally coupling light out of the detection beam path.