Diffusion type

[Stephen Selby]

If I had a 5k bouncing off a 8x8 ultrabounce what would the equivalent diffusion be to get the same light characteristics when aiming through the 8x8 diffusion frame. I'm guessing something like Lee or Rosco 216.

[David Mullen ASC]

Well, you can't really get plastic diffusion in 8x8 frames so you have to think of things like Grid Cloth, Silks, or Soft Frost, etc. in various strengths. It's hard to make an exact comparison to a bounced light situation since the softness depends a lot on how evenly you fill the frame.

 

I often use an 8x8 Light Grid Cloth in front of a large light and then use a 4x4 intermediate frame to soften further and fill the 8x8 frame more evenly -- sometimes I use a 4x4 250 frame and other times a 216 frame as an intermediate. This allows me more control in terms of adjusting the output versus the softness, otherwise I'd just start out with something heavier like an 8x8 Full Grid Cloth.

[Stephen Selby]

Thanks David. I was asking about diffusion because of the following post on Roger's forum by GrantC:

 

"This is certainly less of a 'sheen', but I achieved it by using a 12x12 to soft light the girl, and a 4x4 kino to brighten the profile (same side as the key). The 12x12 key is at 45 degrees, and the kino is on her profile at 180 degrees - essentially creating a two light 'wrap'..." http://i.imgur.com/YjhWXlG.png

 

I like that particular sample but thought i'd try something similar with diffusion. And reversing the wrap order based on your explanation:

 

http://www.davidmullenasc.com/wrap1.jpg

 

Here is the result of one experiment using household bulbs dimmed and some LEE 250 diffusion.

 

So I placed 40w,60w,100w bulbs respectively in an arc and from 7h-9h and this is the result - a wrap:

 

http://stephenselby.com/images/Wrap_DimTowardsCamera.JPG

 

Then I did the opposite 100w,60w,40w like a reverse wrap:

 

http://stephenselby.com/images/Wrap_DimAwayFromCamera.JPG

 

Potentially the sheen is a bit too much and starts to look greasy - perhaps I should redo this with something softer like grid cloth - double diffusion - a larger source such as 8x8 or 4x4 closer.

 

This is a huge steep learning curve changing from film composer to film maker. But I thought rather than sit around waiting for directors to make films that consider music more than a last minute afterthought, why not make one.

 

I'm slowly getting there. Lighting is one of the hardest jobs of the trade so well done you.