Somehow the point of the light measurement is totally lost.
If someone wants to know how much light his adapter is loosing, he should measure how many f stops his camcorder increases using the adapter.
He should do this with the best equipment he can get, including the lens, condensers, GG etc. What's the point doing anything else than that.
If you only want to know what the light-loss is on an oscillated GG compared to a spinning frosted glass or a wax glass, than you should test them with the same lens etc. to measure the difference.
It becomes a strange issue when you don't consider the lens a part of the adapter. It's strange because it's the most important part.

Of course she's-a-flat, and she's-a-not spinning at-a-all.. (what am I... to get burned to the stake?) (;-)<
Start with the sun, get a lens (the focal does not matter much) and smell the brightness increase on your skin.... (;-)< Looks like I posted all those pics for myself and I am just talking to myself.... I had two clips on my site with four different screens: two GG and two focusing screens (one from Beattie) They were all mounted on a "rail"(one after the other one) traveling behind a lens (1.4/50) Camcorder was set for the brightest screen. Nobody watched them, so I took them out. If I still have them, I'll upload them again. None of the present camera manufacturers are using GG!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
They all use focusing screams!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Light it up!

i saw dans video, and it seemed like it was getting more light than before... seriously.

Of course... When I was in the beginning, I project image on GG, then I put piece of fresnel on it, and whole image shine up twice more... I have this tests also on my page... But as Dan said... Everyone is pushing his theory and noone looking on tests from real live :)

EDIT:

Look here... Guess its enough to prove it...
http://web.datriware.com/gfx_photos/articles/p850.jpg

GG and fresnel attached to it. Not beattie, maxwell, or so. Just fresnel.

Yes, but did it "shine up" to the point where the video camera closed its aperture compared to no adapter at all? That is what Dan is saying. But your adapter shows this to be untrue.

That's not accurate. Not many people have tried both a GG and a fresnel or focusing screen, but nobody in this discussion is speaking from theory without "looking on tests from real life." We've all built something in real life; some have tried more combinations than others.

No, what would prove it would be to show the F-stop with the fresnel, compared to the F-stop with no adapter at all. Follow? Just showing one picture of one setup doesn't prove anything at all about increasing brightness and decreasing iris over no adapter at all.

This test is an answer to question what give us more light - GroundGlass or GroundGlass with Fresnel. I think the image is clear. And you do not need to do the test to prove it, you see it. And the test that I gain more light with adapter than without I already did and posted before.

Yes, as I wrote up. But you have to have pretty good lens. I found some 1:1.3 without iris and focusing. Its static lens. And these lens are damn expensive. But anyway... Imho I´m shooting with 1:4 and have no problem. If you saw my nigth movie, its done by 1:4 at 70mm without any post.

Where did you get your fresnel from Dave?

Bought on eBay. Im from Europe, we do not have Interscreen or Maxwell here. I bought Beattie for $45 on eBay (not that one Iam using), you can get it even cheaper, very cheap with scratches for testing purpose (about $15)... Just do not bid, wait till last 30 seconds and then bid !

Did you find that the one you bought on Ebay to be too cheap? Are you using something else that is better?

Yes, I bought all screens at eBay. Its dificult to me, because only bank fees costs me $60. I'am using Maxwell, seems little bit brighter and sharper to me than Beattie. But, Beattie interscreen is good enough. If you want to follow my way, buy one of theese Beatties. They are all plain (no grids) and right now all around $6. I give you an advice : do not bid them now, wait till last minute and then take it.

http://cgi.ebay.com/ws/eBayISAPI.dll...526571900&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll...526571905&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll...526573151&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll...526572476&rd=1

There are more Beatties now (more then ten), go for it if you can (and want).

Awesome, thanks for the info. I am going to bid on some of those. I am not too concerned about the price right now, but I will try the 30 second rule.