Built-in exposure meters are called reflective light meters because they measure the amount of reflected light into the lens. There are three main types of built-in exposure meters:
(1) Centered Meters: refers to meters that measure almost all the light reflected by the area, or scene, you are about to photograph. A centered meter focuses most of the light on close centered subjects, paying less attention to top or distant elements like water and sky.
(2) Spot Meters: these types of meters focus the measuring of light within one specific area. They usually mark the area where the exposure is being measured by tracing a line of the subject or placing a circle around the “spot.”
(3) Matrix Meters: these readers, also defined as multi-segment meters, evaluative meters, or multizone meters, identify the darker areas in a scene and select the area that requires more exposure.
Aside from built-in reflective light meters, there are accessory exposure meters that can be purchased as a complement to your camera. From the accessory exposure meters available, we’ve listed the most important:
Incident-Light Exposure Meters: refers to exposure meters that measure top light from above the subject. Since these meters are effective at measuring total amounts of light surrounding the subject, they are placed between the subject and the camera for best results.
(1) Accessory Reflected Light Exposure Meters: exactly like the built-in readers we mentioned before, these accessory exposure meters measure reflected light into the camera lens. While they are most commonly spot meters, all three types of reflective light meters are available to choose from.
(2) Flash Exposure Meters: these meters simply evaluate the effect of light after flash fires. If the meter determines that exposure is incorrect, it’ll show the proper settings for optimum exposure.