Which speed of camera film handles the wrong light setting best? Photographers sometimes shoot with the wrong aperture (lens opening size). Some film speeds survive this mistake better than others. You test three film speeds in the same camera. The slowest is 100 ASA and the fastest is 1600 ASA. For each speed you shoot at the correct aperture and two stops above and below. You develop the film and measure light levels with a colorimeter. The 1600-speed film showed the smallest difference between its overexposed and underexposed shots. It was the most tolerant to incorrect aperture settings.