Music video by Justin Bieber performing Never Let You Go. (C) 2010 The Island Def Jam Music Group. #VEVOCertified on November 9, 2010. http://www.youtube.com/vevocertified.
Lumens are a unit of measurement of the total brightness that comes from a light source, in this case, a projector. One may also see the term ANSI Lumens. ANSI is an acronym for the American National Standards Institute. In general, the more lumens a projector has, the brighter the image on the screen.
A Lumen (or luminous flux, or Lm) is the total number of packets of light (or quantity of light output) produced by a light source. For example, a 100-watt incandescent lamp emits about 1300 lumens. Read more here. The lux (or lx) is a ratio of illumination (or lumens) over a distance: 1 lux = 1 lumen per square meter. For example, sunlight on average ranges from 40,000 to 120,000 lux, while an office ranges from 300-500 lux, with moonlight representing about 1 lux.