Originally Posted By: EdD270
When I was instructing at FLETC we taught that to have "dazzel effect" a flashlight needed a minimum of 13,000 candlepower. No idea what that translates to in lumens. More is always better. While it was not a true "stun" it would "dazzle" and cause an auto response to squint or close the eyes, and look away even if only for a moment.
Is that the idea they refer to by "stun factor"?


Yea, that is what they refer to. The "dazzling" effect can give you the upper edge in a fight, or give you that second or two head start to get away. It's a small advantage, but it's better than no advantage. Now, when combined with other techniques (like kubotan-style strikes or firearms practice) it has shown to be especially effective.

Now, as far as candlepower vs. lumens, they're two different form of measurement. Lumens measures the lights total output, candlepower measures the brightness of a particular spot of light. They aren't really comparable measurements. Think of a laser, it would be very high on the candlepower scale, but very low in lumens. Typically, lumens is the better measurement for a lights actual effectiveness, with around 60 lumens considered the minimum for an acceptable "dazzle effect."