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Which Diffusion Filter?


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#1 Sam C Roberts

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Posted 25 May 2013 - 01:11 PM

I am about to shoot a movie that takes place in a thick forest. Althought I'd love to be able to shoot only on overcast days this isn't possible so I will have to deal with deep shape sliced up by shafts of bright sunlight coming through the trees. I'm shooting digital (Red camera) and this is not a lighting situation these cameras handle very well.

 

Since it is a kind of fairly tale story I'm thinking.... balance between light and shadow the best I can (we have no big lights just a few 1ks, reflectors and bounce boards which I can use for closer shots of the characters, and put a diffuser on the lens and let the highlights I can't control blow out and glow.

 

What diffusion filter do you recommend for a situation like this?

 

Thanks. 


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#2 David Mullen ASC

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Posted 25 May 2013 - 05:47 PM

If you want a diffused look, it just depends on the look you want.  

 

It sounds like you want the diffusion to also act as a contrast-lowering filter, so I recommend a "mist" diffusion like Tiffen ProMist (regular or black), Schneider Frost (white or black), Tiffen GlimmerGlass, or Schneider Hollywood Black Magic (combination of a 1/8 Black Frost with degrees of HD Classic Soft) or Schneider Classic Soft Blacks (combination of 1/8 Black Frost with degrees of regular Classic Softs.)  Think of a Tiffen GlimmerGlass as a Black ProMist except instead of black specks you have silver specks.

 

Classic Softs have a large pattern of "lenslets" (sort of dimples in the glass) that can produce rings around some lights or an enlarged out of focus blurred fringe around bright edges on longer lenses, and the pattern can come into focus if you stop down too much (hence the finer, smaller pattern in HD Classic Softs & Black Magics).  

 

Filters with black specks in them like Black Frost or Black ProMist can also have issues if you stop down too much and have the patterns come into focus (looks like the lens has dust on it if you stop down too much) though you'd have to stop down quite a bit compared to the pattern in Classic Softs, which is larger and easier to see.

 

What's nice about Schneider Hollywood Black Magics is that the mist element is constant (1/8 Black Frost) but you can vary the degree of softening if you want to do that, as opposed to using a 1/4 Black ProMist or a 1 GlimmerGlass on everything, which also works but it's the same strength on close-ups and wide shots.  And if you jump to higher and lower levels of ProMist or GlimmerGlass, you also change the amount of halation and contrast loss, so there is less matching in look compared to doing a wide shot with a 1/8 Hollywood Black Magic and a close-up with a 1/4.  And since the base of the Hollywood Black Magic is a 1/8 Black Frost, you can also switch to just a 1/8 Black Frost if you want something even lighter than a 1/8 Hollywood Black Magic.


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#3 Sam C Roberts

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Posted 29 May 2013 - 06:40 PM

Thank you for the info David. Would you recommend a stronger diffusion for the wide shots and less diffusion for close ups? With close-ups and medium shots I'll have more control and less trouble with hot spots that with the wide shots.. Will using two different strengths be very noticable?

 

The movie is a kind of fairly tale so the look can be a bit dreamy but not too dramatic. I want a nice balance between the look and the filter's ability to lower contrast and give blown out hot spots a bit of glow.


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#4 David Mullen ASC

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Posted 29 May 2013 - 07:16 PM

It's up to you -- you can use a consistent overall diffusion like a 1/4 ProMist on everything -- most of the period scenes in "Titanic" were shot this way" -- and if you go super wide and want a bit more sharpness, drop down to a 1/8 ProMist.

 

Or you can adjust your diffusion levels scene by scene and shot by shot.  "Legend" for example runs the gamut, there are clean shots, shots with a net filter, shots with a Harrison Black Dot Texture Screen, etc.  To some degree, you have to do this by eye.  Higher contrast scenes can often take more diffusion, or scenes with a strong backlight (which creates an edge, which adds the impression of sharpness), while low-contrast scenes with soft lighting often will need less diffusion.

 

But using one type on most everything also works, it's like shooting most everything with no diffusion in terms of creating a base look.


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#5 David Mullen ASC

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Posted 29 May 2013 - 07:44 PM

Here's a frame from "Excalibur" showing the effect of a white net over the back of the lens and a Harrison Black Dot Texture Screen in front:

excalibur15.jpg


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#6 Sam C Roberts

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Posted 01 June 2013 - 01:18 PM

I'll try and get a variety of clear Pro Mists and just do some tests. Preliminary still photos taken with a cheap diffusion filter gave me the basic look I was after and all the harsh sunlight coming through the tees was nicely smoothed out with a nice glow. Because it is fairly thick forest I think I won't go with the black Pro Mists because an overall optical lift of the black elevels might also be of help and I understand clear pro mists are better for this than the blacks.

 

Thank you again for your generous advice.


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#7 Sam C Roberts

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Posted 29 August 2013 - 01:55 PM

Hi David. Just wanted to thank you for the above advice. I ended up going with a straight (not black) Pro Mist #1 and it worked perfectly. It raised the blacks and softened the hotspots while giving the forest an over all dream-like look. The Director was delighted to say the least. CBTUlookupattree.jpgThese screencaps are a bit compressed looking and the blacks seem to lack detail which actually is there in the R3D files. But they give you a rough idea of what I'm talking about. After doing a lot of testing I'd recommend some netting for the hotspots on faces during closeups but better, try to keep the sun behind the actor and fill. We had no acess to electricity at the location because it was so remote so we did it all with reflectors and bouceboards and it worked out great.CBTUGracelooksup.jpg


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