Exposure
Overall brightness of the camera image
Also known as: Auto exposure · Eye adaptation · EV100 · Exposure value · Manual exposure · Camera exposure
Definition
Exposure is the overall brightness of a rendered image, set by how much light the virtual camera lets in. In photography it combines aperture, shutter speed and ISO, summed up as an exposure value or EV. Game engines use automatic exposure, also called eye adaptation, which brightens dark scenes and darkens bright ones over time, or a fixed manual exposure. The tonemapper then maps the result to the screen.
In production
Decide the exposure first and light for it, since every light's intensity is judged against it. Use fixed exposure for lighting work and consistent screenshots, and auto exposure for gameplay where the player moves between dark and bright areas, with limits on its range. In Unreal Engine exposure is controlled in a Post Process Volume with EV100 values, and in Unity with the Exposure override of a Volume.
Tools that use Exposure
See also
Tonemapping
HDR → display-range remapping
Physical Light Units
Lux, lumens, candela and nits
Scene Too Dark or Too Bright
Auto exposure changes the whole look
Color Grading
Final color and contrast look of the image
Bloom
Soft glow around bright pixels
Volume (Post-Processing)
Unity post-processing and lighting overrides