Light Meter or Exposure Meter
Exposure meter is used to measure the intensity of the light for a particular shot. There are two types of light meters used to measure the intensity of light – incident meters and reflected meters.
The amount of light that is directly falling on an object is called incident light and is measured with an incident light meter. This type of meters contains a white translucent dome called a photosphere, which is mounted on a light sensor. The dome simulates as a three dimensional object and measures the light falling on the object from all the angles.
Every ray of light that bounces off or is reflected by an object is called reflected light and is measured with a reflected light meter. A white object reflects more light than that of a black object. The light at which the area of reflection is measured is called the angle of acceptance.
The most common light meters are called spot meters which has a very narrow angle of acceptance, usually around 1 degree.
Today most of the cinematographer’s use a new type of light meter which has the combination of incident and reflected light meter into one. The major advantage of these types of meters is that you don’t need separate meters to measure them.