Exposure Meter or Light Meter: These are two terms that are usually used interchangeably by photographers. Both are devices for measuring light, however, technically a “light meter” only reports the light’s intensity, whereas an exposure meter measures the intensity of light and translates that data into camera settings needed to make a correct exposure in the given lighting situation. There are two types of exposure meters - incident and reflective. The exposure meter built into your camera is a reflective light meter, meaning that it measures light reflected from a subject. The other type of exposure meter, incident, measures light that falls directly onto the meter. This is the type of meter that is used to measure flash’s intensity.