How to Control a Large Light Source

[Gregg MacPherson]

Robin,

We are talking about the effectively used part of that large screen, and the wattage that lands on that. Looking around the border of that effective area, about half of that large diffusion screen is not being used.

 

Here's a quick drawing that has approximately the proportions of Matt's simulated set/setup. Lamp on the left, "girls" face on the right. You can see the parts of the diffusion screen that are not being effectively used. As a notion, throw them away. Or, better, leave all alone, change nothing, except swap out the source lamp for something about 1/4 the watts, filling the approxamately matted effective diffusion area.

 

Hopefully that's clear. I'm hoping that Matt, who I think probably understands the physics well, or is at least able to simulate it, will drop back into his own thread.

 

Edited December 10, 2015 by Gregg MacPherson

[David Mullen ASC]

I agree that in this case, the flags are a bit too close to the diffusion frame -- on a real set, you'd back the diffusion frame up or the flags out a bit. But the basic principle here is that large diffusion frames need large flags. I wasn't trying to guess the actual measurements and sizes of everything, I was speaking more about the lesson you are supposed to learn here.

[Gregg MacPherson]

I agree that in this case, the flags are a bit too close to the diffusion frame -- on a real set, you'd back the diffusion frame up or the flags out a bit. But the basic principle here is that large diffusion frames need large flags. I wasn't trying to guess the actual measurements and sizes of everything, I was speaking more about the lesson you are supposed to learn here.

 

I never proposed that the flags were too close. I wasn't that interested in that here.

Just to be clear, which lesson, and given by who?