MCD stand for "millicandela" or 1/1000 of a candela. This a unit of light energy of a single color, and in a single direction. For example: if you stand a few feet from a 100W light bulb, your eyes will get about 120 candelas of brightness reaching them--that's 120,000 MCD. The little LED's you see on cell phones may be about 20 or 30 MCD. This is a very rough idea of what it means. For a more formal explanation, go to http://en.wikipedia.org/wiki/Candela and read all about it.
How bright is an MCD?
