The data printer (20) allows date and/or time information to be printed on the film (18) in synchronism with the transport of the film, using an exposure device (21) with a number of light-emitting elements and an optical imaging system (22), for providing corresponding light points on the film. The optical imaging system has a magnification which lies between 0.6 and 1.5 and uses a single lens receiving the light from the light-emitting elements, e.g LED's (21a) which are positioned along a straight line, for deflection onto the film without reflection.
