A light trap, a device for coupling a first beam path to a second beam path, and an illumination device for an optical observation device, as well as an optical observation device. The light trap is for eliminating or preventing stray light, e.g., in the form of scattered light. In order to be able to further improve the elimination of disruptive stray light in the form of scattered light, the light trap is configured in a special way. It has a filter element, particularly a neutral filter element, which is characterized in that an incident light face of the filter element has a concave radius, whereby the incident light face has a specific curvature.