Can the average person measure lumens?

[KingGlamis]

Is there a way to measure lumens for the average Joe? I would assume that lumens can be calculated with math, is this true? But what about real-world tests? Is there something I can buy to test lumens that doesn't cost a ton of money? I'm really interested in modding but would like more accurate test results than just shining lights at distant objects.

Thanks for any help you can provide.

 

[SilverFox]

Hello KingGlamis,

If you go to Flashlight Reviews, you can find what Doug has been using to determine his total output numbers for the various lights. There seems to be a correlation between that an lumens.

If you are serious about knowing the exact lumens, for around $400 you can send a light to a lighting laboratory to have them test for lux, lumens, spectrum and CCT.

Tom

 

[defusion]

you can measure lux with a lux meter for about $20, which is a specific brightness at one spot at a certain distance. if you combine that with the size of the hotspot (the area where the total amount of light is about the same as where you are measuring), you can compare between several lights.
if you already know the lumens a certain light puts out, you can get a ballpark figure to the output of another light of which you measured the output with your own method.

 

[Codeman]

X2 on what SilverFox said. After "calibrating" my setup/technique using a few lights with known lumen ratings, I can get within about 5% of most lights. Given that it takes a 50% change in order for the human eye to register a difference in brightness, 5% is more than accurate enough for me.

Quickbeam's technique works well for incandescent and white LED's. Fluctuations in meters when measuring colored LED's, though, makes it difficult to measure them reliably.