Exposure (photography)
![A long exposure showing stars rotating around the southern and northern celestial poles. Credit: European Southern Observatory](/Images/godic/202501/26/Trailing_stars_above_Paranal0249.jpg")
![A photograph of the sea after sunset with an exposure time of 15 seconds. The swell from the waves appears as fog.](/Images/godic/202501/26/Clifton_Beach_50249.jpg")
![White chair: Deliberate use of overexposure for aesthetic purposes.](/Images/godic/202501/26/Stühle_Froschperspektive0249.jpg")
![Two similar images, one taken in auto mode (overexposed), the other with manual settings.](/Images/godic/202501/26/Auto_vs_manual_settings_comparison,_barn_and_trees0249.jpg")
In photography, exposure is the amount of light per unit area (the image plane illuminance times the exposure time) reaching a photographic film or electronic image sensor, as determined by shutter speed, lens aperture and scene luminance. Exposure is measured in lux seconds, and can be computed from exposure value (EV) and scene luminance in a specified region.