Originally Posted by
PlanoFuji
Okay, I assumed (since your stated values were consistent with) both beams of a car's headlight. And regulations restrict car's headlights to 20,000 candela, while high beams are restricted to 75,000 candela. So my 3 to 4 times is quite accurate...
Aren't these stupid units fun...
Candela and lux are both units that include beam pattern factors. These are a measure of your optics as the light bulb behind them.
Thinking about lighting is fairly simple. Lumens = total number of photons. Candela/Lux = where are the photons are going.
The H7 bulbs on my Subaru are listed at 1450 lumens.
http://www.danielsternlighting.com/t...ulb_types.html
The car has two of them for a total 2800 lumens.
1400 lumens is a good LED light, so there's really only a 3-4x difference if you consider that cars have 2 headlights, and most people don't run 1000+ lumen mtb night lights.
As for reflectors, in bright daylight, I can easily see a 50 lumen blinky light from a quarter-mile away or more. Good luck with a reflector.