Light brightness

I know of at least 4 different bike lists that Alex posts to on a regular basis. I also know that Alex is really good at his "real" job (we sort of work together). And watching his blog, it's clear the guy gets a lot of other stuff done. There's also other non-bike related interests that Alex spends time pursuing (electronics, computer stuff, fish stuff, beer making, home projects, etc). It's not clear to me how he does all this. But some common Alex traits thread their way through all of these pursuits: honesty, curiosity, and creativity.

Anyway, that's the Alex backstory.

The following was taken from a thread on a bike list at work. Some guy posted the chart below and then below that is Alex's reply.

I found it particularly enlightening. Or should I say illuminating? (I've been watching too many Hitchcock intros).

Brand/Model	Price	Claimed Lumens	Measured Lux	$ per lux
Ayup 2010 bar V4 Adventure System (Full Review here)	$233	400	34	$6.85
Ayup 2010 helmet (Full Review here	$233	400	31	$7.52
Baja Designs Stryker	$298	700	52	$5.73
Exposure Toro (Full Review here)	$339	700	36	$9.42
Exposure Diablo (Full Review here)	$249	700	34	$7.32
Exposure MaxxD	$399	960	48	$8.31
HID Technologies Lumen8r Quad	$495	1000	6	$8.25
Lupine Tesla 4 (Full Review here)	$420	700	52	$8.08
Lupine Wilma 5	$459	920	66	$6.95
Lupine Betty	$1,019	1750	165	$6.1
Magicshine MJ-808 (Full Review here)	$85	90	37	$2.30
Niteflux Enduro 8 Single	$249	540
NiteFlux Max Extreme 2	$480	1350	70	$6.86
Niterider Pro 600	$499	600	46	$10.85
Niterider Pro 1200	$649	1200	82	$7.91
TrailLED Darkstar	$420	1200	81	$5.19

Says Alex:

This chart shows while Lumens are such a silly way to measure lighting.

Lux is the intensity of the light over an area. Lumens are the total intensity of the light. You can have something with very high lumens distributed over thousands of square meters and the light wouldn't be noticable at all (so the lux would be very low). The same number of lumens could be concentrated into in one square mm and probably burn a hole through something (the lux would be very very high).

The headlight that I use (a generator headlight called the IQ Cyo) is 60 Lux, but uses a LED that only puts out around 150 lumens (CREE XR-E). The lenses just do a good job of putting the light on the ground in front of the cyclist, and not wasting it lighting up trees that are over the road or trail. The MS has 6x the number of lumens, but puts less light onto the ground becuase the light is being distributed everywhere. A lot of that scattered light is going into the eyes of oncoming cyclists and driver's, blinding them.