Abstract: A dias light device to be placed on the original holder of a reproduction camera for effecting exposures with high enlargement of small originals comprises a housing provided with a window to receive a small original, such as a transparency, a light source in the housing, a light sensor for detecting light from a light source of a reproduction camera and a control system responsive to the sensor for activating the light source in the housing when the camera light source is active. The dias light device is applicable to any existing reproduction camera without any need to connect it with or alter the camera.