seeker333

A comparison of 10 bicycle headlight systems with with good pictures.

https://reviews.mtbr.com/blog/2010-mtbr-lights-shootout/

RapidRobert

Beam shots can be deceptive. Cameras are not linear, and have light metering that can make headlights with more light in the central "hot spot" appear to be brighter than they are. Also, the linked site's use of a lux measurement after bouncing the headlight's output off a white ceiling is also prone to error. Those results are going to be heavily influenced by the light's reflector design. More of the light's output in the "hot spot" means a higher reading.

Beam spread angle, "hot spot" spread angle, output percentage in the "hot spot", and total lumens output are the four specifications that really describe headlight performance. All four are easily measured with a simple luxmeter.

seeker333

I'm reminded of the old saying - a picture's worth a thousand words...

RapidRobert

True. But a picture's also only a single perspective view of a two dimensional scene, recorded with many compromises and manipulations of the information. I'm only questioning the accuracy of the words those pictures represent. The "picture" I recommend is a Warholian four numbers, but the message they convey, perhaps in addition to beam-on-a-wall pics, will provide the "whole picture".

tFUnK

side by side instead of page by page would've been nice.

kleinboogie

Thanks for posting. I just did a DIY and I can see how beam spreads matter depending on the application. Guess I'll do another one. I'm thinking of maxing out 3 XR-E LEDs heatsunk of course and watch the smoke.