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What is a fresnel?


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#1 Adam Orton

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Posted 20 October 2008 - 06:26 PM

OK, if there were a "stupid questions" category to post under, I would gladly place this question there.

I know a fresnel is essentially a light that uses a lens to produce an even, consistent spread of light. (That can be spotted or flooded.)

I was always under the impression that a fresnel light used a piece of specially shaped glass to reorganize the light, but lately I've heard of something called an "Open-faced Fresnel" that produces pretty even light (from what I've gathered) and can be spotted or flooded the same. But it doesn't use a lens; rather, it's just a bulb with a curved mirror behind it...

My question is, what exactly qualifies a light as a fresnel? Is there such a thing as an "open-faced" fresnel?
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#2 Chris Durham

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Posted 20 October 2008 - 06:33 PM

To my understanding, "Fresnel" refers to the lens, not the light. So a fresnel light is a light with a fresnel lens on it. right?

If you look at Arri's lineup, for instance, they have fresnels and open-faces, but the nomenclature doesn't cross. I do think there are probably folks who refer to any directional hard light as a fresnel, but that's incorrect.
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#3 Adrian Sierkowski

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Posted 20 October 2008 - 06:33 PM

I've never heard of an Open Face Fresnel, as Fresnel is, as you mention a lens. Might be an open face which uses a lensed bulb, though.
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#4 Jonathan Bowerbank

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Posted 20 October 2008 - 08:21 PM

I've never heard of an Open Face Fresnel, as Fresnel is, as you mention a lens. Might be an open face which uses a lensed bulb, though.


Open Face Fresnel is usually when a DP or Gaffer is referring to a Fresnel lamp with a swingaway lens, so you can then make it an Open Face/Eye. It takes away the softness produced by the fresnel element and give you a much harder light source, very good if you're trying to mimic hard sunlight.

And yes, Fresnel refers only to the type of lens on the light.

http://en.wikipedia....ki/Fresnel_lens

Edited by Jonathan Bowerbank, 20 October 2008 - 08:22 PM.

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#5 Adrian Sierkowski

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Posted 20 October 2008 - 09:29 PM

Ahh, gotcha on the Open Face Fresnel. I've done that before and just called it a Naked Fresnel on my old Mole 2Ks.
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#6 Adam Orton

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Posted 20 October 2008 - 09:49 PM

Open Face Fresnel is usually when a DP or Gaffer is referring to a Fresnel lamp with a swingaway lens, so you can then make it an Open Face/Eye. It takes away the softness produced by the fresnel element and give you a much harder light source, very good if you're trying to mimic hard sunlight.
http://en.wikipedia....ki/Fresnel_lens



Aha. That clears up so much then. Thanks!
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#7 Michele Peterson

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Posted 20 October 2008 - 11:38 PM

I've never heard of a lamp being referred to as and open faced/fresnel. It's always been one or the other. It might be a regional term. You can make a fresnel into an open faced by doing what is called "poking the eye out" which is just removing the fresnel lens (the glass).

Poke the eye out of the baby!

Edited by Michele Peterson, 20 October 2008 - 11:39 PM.

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#8 James Steven Beverly

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Posted 21 October 2008 - 01:43 AM

Poke the eye out of the baby!


Gaffers have such delicate sensibilities. :rolleyes:

Edited by James Steven Beverly, 21 October 2008 - 01:44 AM.

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#9 David Auner aac

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Posted 21 October 2008 - 10:05 AM

Gaffers have such delicate sensibilities. :rolleyes:


'Hey Joe, please hang the baby, kill the midget and have two blondes standing by for the martini!"

Cheers, Dave
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#10 Michele Peterson

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Posted 22 October 2008 - 12:26 AM

'Hey Joe, please hang the baby, kill the midget and have two blondes standing by for the martini!"


Hang the black and two-leg the red head while you're at it.

Edited by Michele Peterson, 22 October 2008 - 12:27 AM.

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#11 David Auner aac

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Posted 25 October 2008 - 02:21 AM

Hang the black and two-leg the red head while you're at it.


Hehe, that's a nice one too. The one I mentioned above was paraphrased after a part of Harry Box's intro the the Set Lighting Technician's Handbook which is an excellent book. One day, we should collect that kind of joke from all around the globe. Might be a very funny read!

Regards, Dave
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