An exposure meter is a device used to measure the amount of light in a scene, either falling directly on the subject (incident light) or reflected from it (reflected light). Photographers use exposure meters to determine the correct combination of aperture, shutter speed, and ISO to achieve a properly exposed image. Accurate metering ensures that highlights and shadows retain detail and that the final photograph reflects the intended brightness and tonal range.
Exposure meters can be handheld instruments or built into cameras, offering readings in EV (exposure value), f-stops, or other units. Understanding how to use an exposure meter is crucial for both film and digital photography, particularly in manual shooting situations, studio lighting setups, or high-contrast environments where relying solely on automatic camera metering may result in incorrect exposure. Proper use of an exposure meter enhances consistency, precision, and creative control over photographic results.