New techniques for the operation of electrostatically focussed and deflected image converter tubes in the framing mode have been developed. Solid-state devices are used throughout. The camera may be programmed to provide various numbers of frames, each exposure duration, and each frame interval, being individually adjustable. A separate programming unit permits the operator to preset the required sequence, the appropriate data being transferred to a fast-access memory in the camera. Triggering of the camera then initiates the stored sequence.