Ambient light reading is the measurement of the existing light in a scene, such as sunlight, daylight, or artificial sources like tungsten or fluorescent lighting. Photographers use ambient light readings with a light meter to determine the correct exposure settings, including shutter speed, aperture, and ISO, without adding extra illumination. Accurate ambient light measurement is essential for achieving balanced exposures, maintaining natural color tones, and capturing the intended mood of a photograph. It is widely applied in portrait, landscape, and interior photography where the quality and direction of natural or available light significantly affect the final image.