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Infrared filter?


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#1 Rhys Cooper

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Posted 08 April 2009 - 05:55 AM

What exactly do infrared filters do? How do they work?

How could we use them for film?
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#2 Michael Kubaszak

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Posted 08 April 2009 - 08:18 AM

they filter out infrared light. there is no use for them on film. they are used primarily on the RED.
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#3 Chris Keth

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Posted 08 April 2009 - 12:12 PM

One kind of infrared filter, as Michael says, is designed for filtering out unwanted IR spectrum light. This is usually what's meant in motion picture work and the RED has made them much more common due to the requirement for so much ND for exteriors. ND is neutral for visible light but doesn't do so well for IR spectrum so you end up unevenly filtering more visible light than IR.

There is another kind of filter commonly called an IR filter filters out everything except deep red and IR spectrum and is used for infrared shooting. I assume that's not whta you're talking about, though.
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#4 Jamie Metzger

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Posted 08 April 2009 - 12:44 PM

One kind of infrared filter, as Michael says, is designed for filtering out unwanted IR spectrum light. This is usually what's meant in motion picture work and the RED has made them much more common due to the requirement for so much ND for exteriors. ND is neutral for visible light but doesn't do so well for IR spectrum so you end up unevenly filtering more visible light than IR.

There is another kind of filter commonly called an IR filter filters out everything except deep red and IR spectrum and is used for infrared shooting. I assume that's not whta you're talking about, though.


I wish I had them on a recent shoot. Outdoors, I was pusing the Kelvin to 10,000, and the image was still looking purple, especially in the clothes of the actor.
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#5 Chris Keth

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Posted 08 April 2009 - 01:22 PM

I wish I had them on a recent shoot. Outdoors, I was pusing the Kelvin to 10,000, and the image was still looking purple, especially in the clothes of the actor.


Yikes, that's no good. Completely on the other side of the spectrum, I did a feature with the red in October and we got an IR filter and only used it a couple of times.
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