Other things can also effect your light output such as bulb age for example. Best way to be sure that light A is putting out equivalent to light B in any given situation is by light meter I realise thats not helpful as you said without calculating on a light meter.
Another way would be to point your cam at a white wall with the light head and use a waveform to read the ire. And then swap lights and do the reading on the second unit / make changes until they match ire level.
Thread: Scriming lights
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09-06-2012 07:30 PMSDC Productions Gold Coast Aust. http://sdcproductions.com.au
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ECHOES ON THE WAVES - IN EDIT http://www.facebook.com/home.php?sk=...643079268&ap=1
09-15-2012 11:53 AM
Full/Double scrim = 1 stop
Half/Single scrim - 1/2 stop
Full/Double scrim (1-stop) [Half the light]
1,000w = 500w
Half/Single scrim (1/2-stop) [Quarter of the light]
1000w = 750wSo, if Im adding a gel to it;
1000w + Full CTB (1-stop) = 500w
1000w + 1/4 CTB (1/4-stop) = 750w
09-15-2012 01:44 PM
In practice Full CTB reduces the intensity closer to 1.7 stops of light. Often 2.
09-15-2012 01:55 PM
1/4 CTB cuts the light by a little over half a stop too. Quarter, half, and full don't correspond to the F stop reduction, it's solely the color temperature change.
09-15-2012 03:27 PM
So, CTB is roughly 2x the amount stated:
1/4 CTB = approx 1/2-stop
1/2 CTB = approx 1-stop
1 CTB = approx 2-stops
what about CTO gel?
how much light loose would it be? if its possible to calculate.
1/2 CTO =
3/4 CTO =
1 CTO =
09-15-2012 04:39 PM
From "Motion Picture and Video Lighting" By Blain Brown.
Conversion factor and light loss.jpg"The enemy of art is the absence of limitations"
"To me the great hope is... people that normally wouldn't be making movies will make them and suddenly some little fat girl in Ohio will be the new Mozart and will make a beautiful film using her father's camera-corder and the "Professionalism" of movie making will be destroyed forever and it will finally become an art form."
-Francis Ford Coppola.