21Concepts in PhotographyHow the aperture setting, shutter speed,and ISO sensitivity control exposureThe aperture setting, shutter speed, and ISO sensitivity are closelyinterconnected in photography. The aperture setting controls the openingthat regulates the light that enters the camera, while the shutter speeddetermines the length of time that light is allowed to enter. ISO sensitivitydetermines the speed at which the film reacts to light. Together, thesethree aspects are described as the triangle of exposure.A change in shutter speed, aperture value, or ISO sensitivity can be offsetby adjustments to the others to maintain the amount of light. The results,however, change according to the settings. For example, shutter speed isuseful in expressing movement, aperture can control the depth of field,and ISO sensitivity can control the graininess of a photo.Settings ResultsAperturevalueWide aperture= more lightNarrow aperture= less lightWide = small depth of fieldNarrow = large depth of fieldSettings ResultsShutter speedFast speed= less lightSlow speed= more lightFast = stillSlow = blurryISO sensitivityHigh sensitivity= more sensitive to lightLow sensitivity= less sensitive to lightHigh = more grainyLow = less grainy
