halocon said:
are lumens and candlepower the same thing? if not, how many lumens are in one candle power or vice versa?
Candlepower measures light at peak levels of the spot. Light meters measure this and it is a good measure for throw and peak intensity.
Lumens are different. It is a measure of total light output and are measured with a very expensive intergrated sphere $$$$$.
Doug at Flashlight reviews measures candlepower (or lux) but uses a box with reflective material to guesstimate total light output. All the light put out gets reflected onto a light meter giving a rough idea of how much total light the flashlight puts out. Not as accurate as an intergrated sphere but considerably cheaper and close enough.
Think of it this way, a GE 60 watt light bulb is rated 848 lumens or total light output. Put it in fixture in the garage and it becomes a large flood of light that would not registar very high on a candlepower meter. Now throw it in a deep reflector to collect the light and throw a small intense spot of light. That would peg the light meter so optics matter with candlepower but not with lumens (unless the reflector is very poor).
