What type of light does the light meter in most SLR cameras measure?

The light meter in most SLR cameras measures reflected light, which is the light that bounces off the subject and enters the camera. This type of measurement is essential because it helps determine the exposure settings needed to properly capture the scene as perceived by the camera. When the meter reads the reflected light, it considers the average brightness of the subject within the frame, adjusting the aperture, shutter speed, and ISO accordingly to achieve a well-exposed photograph.

In more detail, reflected light measurement takes into account the luminosity of the scene as it is reflected off surfaces, which is crucial since the camera's metering system is designed to produce neutral gray tones for average scenes. This means it will process scenes to ensure that highlights and shadows are balanced based on the reflected light from the specific subject being photographed.

While incident light, which is the light that hits a subject before being reflected, is crucial for certain types of photography (especially in controlled environments), most SLR cameras predominantly work with reflected light metering for everyday photography. Ambient light usually refers to the natural light present in a scene, and filtered light pertains to light that has passed through a filter, neither of which are directly measured by the typical built-in light meter of an SLR camera.