The present invention relates to a method for the optical self-diagnosis of a camera system and to a camera system for carrying out the method. The method comprises recording stereo images obtained from in each case at least two partial images (2, 3) creating a depth image, that is to say a disparity map (5) given by calculated disparity values, determining a number of valid disparity values (6) of the disparity map (5), and outputting a warning signal depending on the number of valid disparity values determined. A device for carrying out such a method comprises a stereo camera (1) having at least two lenses (7,8) and image sensors, an evaluation unit and a display unit.