Abstract: Hand-held photographic light meters which may be of either the incident light or the spot variety are equipped with means of transmitting the light intensity measured to a suitably equipped automatic camera by means of a modulated beam of infra-red radiation. In this way the camera is set accurately regardless of the reflectance of the subject. Continuous or flash or a mixture of the two lights may be used. The camera has to be modified to receive the infra-red radiation in Type A of the invention while in Type B a special receiving unit which mounts on the hot-shoe is used to give a less flexible performance. More than one camera may be set simultaneously and most of the features of the automatic camera are retained.