I am new to the board ! Looking at the specs. for a Stinger vs. Surefire and I noticed that the Candlepower spec for Stingers is 15,000 ! how does that convert to a lumen reading to compare against the Surefire ?
The short answer is that it doesn't. They measure different things.
Lumens measure the total light output, while candlepower measures the brightest point within a beam. A high lumen bulb with no reflector or optics to focus the light into a beam will have low candlepower and a low lumen bulb with a narrow beam reflector/optics can have high candlepower.
It would be nice if flashlight manufacturers gave an ACCURATE specification for both, but I don't think I've seen any that do.. (Maybe Mag? Don't they have both on their spec sheets now?)