Term - Twilight factor
|Twilight factor||SWPP Photographic Glossary|
Sunday 26th September 2021
An indication of the brightness value of binoculars. It's similar to relative brightness, but you multiply the objective lens with the magnification and then find the square root of the resulting number. A higher number indicates the binoculars will be better for use in low light.
Information provided by: SWPP