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Using ND gel in front of the lens


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#1 Luis Filipe Montanha

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Posted 27 August 2012 - 07:57 PM

Hi there everyone!

It's possible for me to use a Neutral Density gel (rosco) in front of the lens? In our production, we have 3 glass ND's, from Schneider... but we need more to cut light in a scene with hard sunlight (we are working with Sony Nex-fs100, which have a native 800 ISO - it is hard to control in some situations).

Can I loose quality in the final image?

Thank you all!

Best regards
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#2 Lucas Griego

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Posted 27 August 2012 - 08:38 PM

Hi there everyone!

It's possible for me to use a Neutral Density gel (rosco) in front of the lens? In our production, we have 3 glass ND's, from Schneider... but we need more to cut light in a scene with hard sunlight (we are working with Sony Nex-fs100, which have a native 800 ISO - it is hard to control in some situations).

Can I loose quality in the final image?

Thank you all!

Best regards


Yes you can. It takes some experimentation to get it to work and it's not without issues (eg. getting it flat and not losing image quality).
But it can be done in a pinch if you can't get your hands on any other ND filters or make adjustments somewhere in the chain.
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#3 John David Miller

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Posted 27 August 2012 - 09:47 PM

The gel material is like a dust magnet. Maybe you can attach it to an optical flat and sandwich it between a glass ND filter. Like a glass ND .3, Rosco ND 1.2, optic flat to give you a tasty ND Oreo. Keep the gel tight and exterior light off it.

I believe you get problems with color shift after 4 stops of ND. At which point ND + IR is needed. I'm sure one of our ASC members could give more a detailed explanation.
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#4 Stuart Brereton

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Posted 28 August 2012 - 04:05 PM

It is possible, but definitely not advisable. ND gel is very far from optically clear. Imperfections in the base of the gel, creases, fingerprints and dust can all impact on your image quality.

If you've run out of ND, try using a polariser to cut another couple of stops.
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Tai Audio

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rebotnix Technologies

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Rig Wheels Passport

FJS International, LLC

Glidecam

CineTape

Wooden Camera

Willys Widgets

The Slider

Aerial Filmworks

Abel Cine

Paralinx LLC

Ritter Battery

Visual Products

Metropolis Post