Exposure is the amount light of per unit area striking an electronic image sensor and is determined by the camera shutter speed, lens aperture, and scene luminance. The camera’s ISO setting reflects the electronic image sensor’s sensitivity to available light also affects the final image result. Variations of each of these components has a major impact on the photograph.
Aperture affects the depth-of-field or the sharpness in front of and behind the plane of focus. The smaller the aperture, the greater the depth of field. Shutter speed affects the blurriness or apparent motion of the photograph. The slower the shutter speed, the greater the blur of a moving subject.
Lens Focal Length
ISO affects the graininess or noise of the final image. The higher the ISO, the more grain or “noise” will be seen in the photograph. The exposure triangle attempts to demonstrate the effect of these variables.