Why would you consider lumens for photography? Taking a picture you’re just going to rely on the sensor in your camera, what settings to use. Lumens change constantly as the cells drop voltage and the emitter heats up.
Thanks TK
I cannot do that but I will be getting one for my Son to take to Burning Man and he will have no problem upgrading.
And mine might get done at Christmas, if we have them by then 
Knowing the approximate lumen output, and taking into account inverse square law, allows the photographer to select the correct exposure for the illuminated scene. For example if I wanted to make a 250 lumen beam shot look like a 1000 lumen beamshot, I could just increase ISO from 100 to 400 assuming other exposure parameters are constant.
For light painting photography, knowing the light output, and predicting the required exposure can save many minutes of faffing around getting the right exposure.
Does anyone have a good feel for how much light is needed from the Q8 to use one of the diffuser designs we have seen to make the Q8 an emergency room light.
I realize that is a serious SWAG, but that is my intended use and I would be interested to know how roughly how long a run I would get at a generally useful power drain on the Q8.
Or I can just wait for my light.
^
No idea
Is it going to be a “backup light” for the ER? Or do they have you all on a tight budget? 
The subject of my post wasn’t lumens but a definitive measurement of light. Reread my post. If it doesn’t say that that is what was intended.
Please try to understand the intent of a post.
Edit: Yeah, I went back, it definitely does NOT say or mean what you said I wrote. I was quite clear. Read it word for word. Hint: look for the word “definitely”.
You didn’t write the word “definitely” you said “differently” which left it wide open.
To be really very very precise, it wasn’t “different” but “absolute” which is pretty much synonymous to “definitive” in this context. The presence of the word “different” in that same message was purely coincidental or to say the leaast somewhat unrelated. So we’re discussing semantics after all… or nitpicking, or misreading our own posts. 
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No, I think my English was pretty clear.
But if someone wants to keep digging a hole I’ll definitely let them.
Lumens are great as a way to get an idea how a light will look when ceiling-bounced, or a rough idea how much power it uses. It says very little about how far the light will throw though, or how bright the illuminated subject will appear.
For photography, and for throwers, lux / candelas are the important metric. It directly measures how bright a surface appears.
The lux per lumens value is a quick way to get an idea how throwy or floody a light is.
The whole cube-root thing is just an approximation for the curve shape required to make a light look like it’s getting brighter at a constant rate, assuming nothing else is changing at the same time. I use it for calculating the ramp and mode spacing, and for estimating how things might appear in person. It’s totally arbitrary though, just a best-practice guideline.
If this is still ongoing, I’d like to add my name to the interested list for one.
Turn a pie plate into an inverted V cone shape located part way up a lamp shade and set the whole thing above the light. I’m pretty sure one of the low-medium modes would easily light up a room. What mode to read by you’d need to determine case by case.
Please add me to the list for 2.
Please, add me to the list for 2 more (#1233). Thanks!
Don’t know if this has been mentioned but if made available they could probably sell more than a few of the mcpcb’s and drivers.
seems a hard club to join
anything to do with my lisp
or my insistingcy ?
Must be the lisp. Miller mentioned he put you on the list here but I cant see you on the list either.
Maybe you have been a naughty boy? 
Only to light up a room for emergency situation the q8 is for sure a good choice but maybe not the best. If you go with more ah (4x26650, or even more) and less AMP (1 led running under low/medium electrical load) and a bigger reflector imo you will get more running time. But i am talking about the need of more than 3-4 nights.
Personal expierience: Palight boss1, 10 nights on a boat as Toplight, over 70 hours in low (astimated 250 lumen, more than enough w big reflector and nearly clear diffusor; also for a room 4x4m) with 4 liitokala 26650/5000mah.
Hey! the list was not upated from before that, now it is up to date till this post