Exposure is all about making sure the sensor gets the right amount of light. Without camera exposure controls, pictures taken at night would be pitch black, and those taken in bright daylight might be burned out. There is actually a fairly narrow ‘window’ of light intensities which sensors can record, and real-world lighting conditions vary […]
EV (exposure value)
A numerical value given to the amount of light in a scene. For example, bright sunlight might produce an EV of 17. In practice, cameras deal only in shutter speeds and lens apertures and you're only likely to see EV values on handheld light meters.