stack nd before diffusion? or diffusion before nd?

J Davis

J Davis

Veteran
I would lean towards having the nd on the outside before the diffusion but I thought I would check with the dvxuser gurus first!
What say ya'll?
 
Usually in that scenario I would place the ND on and then shoot through a diffusion frame. So if I were to use straight lee diffusion or the like I would put ND on the inside.
 
Thanks Noel. What about if they are both screw on filters for dslr lenses?

Would the nd reduce or negate the effect of the diffusion if it were on the inside?
 
I can't imagine there being a quantifiable difference - but like most things in this biz, test test test.

They both do such different things, and are sandwiched in glass... I only think about this stuff if something needs to go in the rotating stage of my matte box (a polarizer usually).

I've never used diffusion for video - for stills, I'd grab an acetate sheet off a 4x5 trasparency and stick it over the lens. Sometimes with a swipe across my forehead if we wanted to go super-dreamy. Nothing like a client saying "that is soo pretty" and thinking "yeah, that's forehead oil..."
 
I actually would love to run tests but at the moment I don't have much time which is why I turned to the dvxuser pool of knowledge.

My understanding of an ND is that it can't make pure black any blacker yet it can make white's darker so I'm guessing that it affects highlights more than darks.
If this is the case I figure it would make no sense to have the diffusion on the outside of the ND as you would be diminishing its effect.
 
J Davis said:
I actually would love to run tests but at the moment I don't have much time which is why I turned to the dvxuser pool of knowledge.

My understanding of an ND is that it can't make pure black any blacker yet it can make white's darker so I'm guessing that it affects highlights more than darks.
If this is the case I figure it would make no sense to have the diffusion on the outside of the ND as you would be diminishing its effect.
Click to expand...

Well that is true if you are underexposing the shot because you can't have less than zero photons hitting the sensor. I use an ND filter all the time and when I rotate it, I do so till just before my blacks go total black as I don't want to underexpose them. Of course, in bright sunlight with lots of shadows, and a limited dynamic range, I don't really have a choice, I have to pick highlights or shadows and it really depends on the type of scene whether I mind which I don't have.

I would think you'd want to place the diffuser where it looks best. If you move it farther from the lens, I'd imagine the diffusing capability changes. I'd take your diffusor, not screw it on, and hold it out in front and pull it to and from the front of the lens to see how it changes over distance. But, given that short of a distance difference, it probably doesn't make much of a difference :)
 
I should mention I am using the FaderND which is an adjustable ND filter. Basically two polarizing filters you can rotate one of them. Works good on the lens I use but there are tests that on some focal lengths they cause a change in color!
 
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