The rotary shutter and the film drive are like those used in cine cameras. When the shutter release is pressed, a light-blocking shield lifts and the shutter disc rotates a full turn exposing the film through its open sector; when the pressure is released the light-blocking shield returns to its position behind the lens, and the spring motor advances the film and recocks the shutter. This is almost instantaneous. With practice a photographer could take 4 or 5 pictures a second. Each winding of the spring motor was good for about 25 pictures, half a roll of film. Shutter speed was determined by spring tension and mechanical delay since the exposure sector was fixed. The Robot I had an exposure range of 1 to 1/500, and provision for time exposures.