Old school but wow!

[alpg88]

When i bought my fist e2 with a bulb it blew away my 4d maglite, could not even compare, however, surefire claimed e2 bulb made 60lm, while maglite xenon 4 cell bulb made around 90, but to my eye SF was way brighter. so if SF claimed m4 made 350lm i would imagine it would put some 1000lm light to shame. seems like they under rate their lumens by half or even 1/3, at least that is what it looks like.

 

[chillinn]

I have suspected maybe something else is going on with Surefire and lumen ratings from other sources, such as Tad Customs. Taking two Tad Customs lamps properly driven side by side, the A6010 rated at 150Lm and the A3718 rated at 140Lm, the A3718 is clearly brighter. So my hypothesis is that Surefire and Tad and some others aren't giving lumen output at turn on, but some kind of average or perhaps after some token amount of time, like two minutes or five minutes or something.

Point is, maybe the MN61 puts out a full 700Lm at turn on, but averaging that with its output at, say, an hour and a half, maybe 0Lm, gives us 350Lm.

I haven't ever seen anything, don't really have anything, to support either idea.

 

[thermal guy]

Well I was told that SF lists out the front lumens where as Lumens Factory lists the bulb lumens. And SF definitely underrates their stuff.

 

[chillinn]

I don't really understand the difference. The lumens from the bulb mostly hit the reflector and shoot OTF. Whatever doesn't becomes spill. Can anyone explain the difference between bulb lumens and OTF? Where else do lumens go other than OTF?

 

[thermal guy]

I stole this but it should help

"
The phrase 'Out The Front Lumens' refers to the light that is projected from a flashlight out the front of the light and is not representative of the number of lumens that would be emitted if the bulb was being powered on its own without the flashlight surrounding it. Therefore, to measure the actual light output of a flashlight, an integrating sphere is used to capture all of the light and distribute the light equally in order for it to be measured accurately.

OTF lumens are typically 25% – 30% lower than rated lumens."

 

[Olumin]

Of cause there is going to be some light absorption by the reflector & lens, but I wouldn't have thought that it is that significant. Considering that the light transmissivity modern AR coated optics is well above 90%, most of the inefficiency must come from the reflector then. That would imply that a common AL reflector is about 70-75% efficient at reflecting visible light.

Maybe its time for silver coated reflectors in a noble gas atmosphere. Lets go all the way boys & girls. Of cause that would mean sealed (non-disassemblable) head units. Thats already the case with most modern lights tho, lol.

 

[chillinn]

Maybe its time for silver coated reflectors in a noble gas atmosphere.

Since most of the energy in incandescents is in the infrared, I'd suggest pure gold reflectors, and since gold doesn't tarnish, no need for special atmosphere.

 

[sgt253]

This might help "shed a little light on the subject."
https://www.candlepowerforums.com/threads/surefire-lumens-ratings-are-wacked.166808/