Back to: The Exposure Triangle: Aperture, Shutter Speed, ISO
Every photograph’s exposure is controlled by three interacting settings — aperture, shutter speed, and ISO — and understanding how they work together, rather than relying entirely on automatic mode, is the real foundation of camera control.
Aperture and Depth of Field
Aperture controls both how much light enters the camera and how much of the image is in sharp focus — a wide aperture creates a shallow depth of field, while a narrow aperture keeps more of the scene sharp.
Shutter Speed and Motion
Shutter speed controls both exposure and how motion is rendered — a fast shutter speed freezes movement crisply, while a slower shutter speed can blur it, either as an unwanted mistake or a deliberate creative choice.
ISO and the Noise Trade-Off
ISO controls the camera’s sensitivity to light, but raising it to compensate for a dark scene introduces increasing image noise or grain, making it the setting generally adjusted last, after aperture and shutter speed are set.
Common Pitfall
Adjusting one exposure setting to fix a problem without considering how it affects the other two often introduces a new, different problem in its place.
Action Step
Set your camera to manual mode and take the same shot three times, changing only one exposure setting each time, to see its individual effect.
Educational content only, not professional advice. No outcomes, promotions, or results are guaranteed.