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Quick Question On 85 Filter


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#1 Adam Keller

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Posted 06 May 2007 - 06:39 PM

I just have quick question about the 85 filter. If I'm shooting an indoor scene with a large window and my main source of light hitting the subject is from the light coming in I know I use an 85 filter to eliminate the picture from being to blue.

However if I'm also using some tugsten lights (unfortunatly without any CTB gels) to act as fill and may add some more "motivated light" will there be a color difference?

Thanks
Adam
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#2 David Mullen ASC

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Posted 06 May 2007 - 06:45 PM

A color-correction filter shifts the color temp of the overall frame, but it doesn't fix individual lights that mismatch in color temp -- that difference remains. So by using the 85B filter on tungsten stock to correct 5500K daylight to match the 3200K balance of the stock, any uncorrected 3200K lights will look very orange.
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#3 Adam Keller

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Posted 06 May 2007 - 07:30 PM

Thanks. So if I want to correct those lights I need to gel them, right?
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#4 Dominic Case

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Posted 06 May 2007 - 08:46 PM

Yes right.

For the moment, forget what you have on the lens. All your light sources need to match each other. So if you have tungsten lights and daylight windows, you either need to gel the lights or the windows.

Assuming you gel the lights, you now have everything daylight coloured: so you need to filter the lens with an 85 to get it orange enough for your tungsten-balanced filmstock. Of course that means that you are filtering the light from the lights twice, thereby losing at least 2 stops of their light. Sometimes, depending on the set-up, it is better to filter the window with a large 85 gel. Then it matches the tungsten lights you have inside, and alsoyou need no more filters on the lens.
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#5 Frank Barrera

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Posted 06 May 2007 - 09:38 PM

in addition keep in mind that your fill lights do not necessarily have to match the daylight coming in through the window. it could be warmer. ie: if you're shooting tungsten film and you use the 85B on the lens you could put only 3/4 CTB or 1/2 CTB on your tungsten units. this would give some warmth (but not too much) to your fill and give you some more stop out of them. but of course it all depends on what effect you are attempting to achieve.
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