Transcription: The slower the shutter speed, the greater amount of light that reaches the film. Reducing the shutter speed one full stop from 1 one-thousandth to 1 five-hundredth of a second doubles the amount of light striking the film. Opening the aperture one full stop from f 5.6 to f 4.0 doubles the amount of light that reaches the film. Similarly, changing film from ISO 100 to ISO 200 doubles the sensitivity of the film so that half of much light is required to achieve an equivalent exposure. For example, let's say for ISO 100 film, your camera's automatic exposure system produces a shutter speed of 1,1 ...
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