Lumens may mean the total power emitted from a source, or the total landing on a particular surface. The projector is specified in terms of light landing on the projection screen - a lot of light is lost internally. The LED is probably specified as total theoretical light power. Further, Lumens specifically measures light output *as perceived by the human eye*. By pulsing the LED at higher than rated current, "the human eye" may perceive significantly more light than running the LED at its DC rating. Keep in mind, however, that in most cases lumens are really only comparable within each product. Projectors use ANSI lumens, but you can't compare them to lightbulb lumens, nor LED lumens. Just like there are a million ways to measure gas mileage, there are a million different models of the human eye, and therefore a million ways to measure light output. -Adam On Thu, Feb 4, 2010 at 2:41 PM, YES NOPE9 wrote: > Cree announces a new LED product..... > http://www.cree.com/products/xlamp_mpl.asp > > The LED package is rated at a max of 1500 lumens. =A0 My LCD projector > is rated at 700 lumens using an expensive bulb that puts out lots of > heat. Probably a Hi-pressure Xenon bulb. > > What is the comparison between these two light sources ? > > Gus > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist