Controlling Exposure

What are the key principles needed to control the exposure of your image? What does each of them do?

    The key principles needed to control the exposure of your image are the Aperture, ISO or gain, and shutter speed.

    The aperture is a ring that opens and closes to let more or less light into the lens and also dictates the depth of field. By letting in more light, the image appears brighter and more exposed, and letting in less makes the image darker and less exposed. Depth of field is the range that things on camera are in focus. The range changes based on the size of the aperture; large apertures have a shallow DoF and smaller apertures have a deeper DoF. 

    The ISO or gain is the digital version of Film Speed on movie cameras. The gain controls how sensitive the CCD: the higher the gain, the more sensitive the element and the less light needed in order to be registered. This means that the exposure increases the higher the gain. However, when the gain is higher, the bigger that the grain is and more noise will appear on camera. 

    The shutter speed dictates the amount of motion blur. A slower shutter speed lets in light for a longer period of time and makes motion blurrier while a faster shutter speed makes motion more jittery. This also affects the exposure as a slower shutter speed raises the exposure and the faster shutter speed lowers the exposure.