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Efficacy (lm/W)

Posted: Sun Sep 02, 2007 4:26 am
by andras85
Hi!

Unfortunately I dont understand the Efficacy(lm/W) setting. I found some items on Wiki:

1lumen = 1/638 W than why can I set the lm/W scale?

Posted: Sun Sep 02, 2007 4:59 am
by CTZn
in short its a measure on how much of the involved energy (watts) is actually converted into light. As you know the biggest part of the energy is converted into heat instead, that's why you need to know the relationship Lm/watts. Watts alone are not enough to get a physical representation of light when electrical lighting devices are involved, because of that energy deperdition. Efficacy is a measure of the remaining energy dedicated to lighting.

Posted: Sun Sep 02, 2007 6:15 am
by andras85
Hi!

I saw looked around in hungarian topics and I understand everything.
Thank you very much for your help.

Posted: Sun Sep 02, 2007 8:25 am
by Zom-B
Just a hint Andreas, before you find it by yourself...
The the Efficacy (lm/W) setting only works with sunlight, not with env maps!

Posted: Sun Sep 02, 2007 9:09 pm
by andras85
OKé...thanks

Posted: Tue Sep 04, 2007 8:14 pm
by mrCarnivore
ZomB wrote:Just a hint Andreas, before you find it by yourself...
The the Efficacy (lm/W) setting only works with sunlight, not with env maps!
But the efficiacy still is for the emitters and not for the sunlight itself, right?