The Pentax ME Super and the Minolta XE-7 have an indicator to show if film is winding properly. Seems overkill as you can judge this by looking at the rewind knob turning as you advance the film. This feature would be most helpful in cameras that mount their flash on top of the rewind knob and prevent you from seeing it turn with film advance like the Minoltax XK or Nikons F, F2 and F3. But these cameras don't have this feature.