When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. SEATTLE—Primes are single focal length lenses, which can be designed with a relatively few ...

The main job of a lens is to concentrate (focus) light rays so the film or digital sensor can record the scene. Put simply, the distance it needs to make the light rays converge completely is called ...

When light moves from air into glass or plastic it is refracted close refractionProcess by which a wave changes speed and sometimes direction upon entering a denser or less dense medium, eg a light ...

Replay: Do we really need to keep using 35mm as our baseline for focal lengths, or is there a much better way? Why do we keep reading descriptions like ‘3.7 mm to 92.5 mm (equivalent to 28.8 mm to 720 ...

The Sigma 20mm f/1.4 DG HSM Art lens features an optical design comprising 15 elements in 11 groups, including F low-dispersion (FLD) and special low-dispersion (SLD) elements, alongside super ...