What do I get if I stack two black promist 1/4 filters?

[Stephen Pruitt]

Do I get a black promist 1/2? Or a mess?

Thanks much.

Stephen

 

[Paul Ellington]

Don't be afraid to try anything ... light a candle turn off the lights and see what you see...

 

[emil tanem]

Correct me if I'm wrong..

You do not get 1/2, but it is very close. Compare to the way NDs work.
1/4 takes 25% light which leaves us with 75%. the next 1/4 then takes 25% of that which leaves us with 56% - not 50%
Don't mind the numbers too much, just remember that no, it's not exactly the same..

Since you're asking about black pro mist and not ND, I'm afraid you might get a mess under certain circumstances. I would definitely avoid it

 

[D Fuller]

Paul is right. Put it on the camera and see what you get. Could be cool. Could be mush. :-/

 

[jimhare]

Also remember you can get a pretty cool ProMist effect in RCX now using Alchemy. Do some tests with that as well, comparing the same shot done with and without ProMist. Might be better to shoot clean and dial it in during post.

 

[Stephen Pruitt]

I've often wondered about that, Jim. I'd hate to bake something in and then decide later I really wanted. . .

Stephen

 

[Marc Wielage]

Elsewhere, David Mullen makes a good case on when to do filtering in production, and when to do it in post. To me, even though the effects are somewhat different, I think it's critical not to go too far in production, because you can never take filtration out once it's in -- especially diffusion. But we can always add more in post with defocus, especially highlight defocus and blur.

 

[Christopher Budnick]

Marc, could you link to the post? Would love to read it.

 

[Shawn Nelson]

Also remember you can get a pretty cool ProMist effect in RCX now using Alchemy. Do some tests with that as well, comparing the same shot done with and without ProMist. Might be better to shoot clean and dial it in during post.

Huh? No offense...but BPM != Alchemy. Alchemy is sort of a contrast with saturation control, BPM affects the light in a way that introduces bloom, contrast, saturation and more.

 

[Ryan De Franco]

I think he may have been referring to the Alchemy group, which includes the "skin" tab, under the assumption that BPM is purely for "softening the look..."

which it does, but the other characteristics are optical. I've never seen it faked in post in a way that really compared to the 4" piece of glass.

 

[Sam Winzar]

I believe Jim is talking about adding negative values to the Alchemy slider. You get quite a nice diffusion effect. I still think nothing beats doing it optically, but doing it in post gives you a lot more options to finesse it and get exactly what you want.

 

[Rob Ruffo]

Also remember you can get a pretty cool ProMist effect in RCX now using Alchemy. Do some tests with that as well, comparing the same shot done with and without ProMist. Might be better to shoot clean and dial it in during post.

Post is not the same at all. I love post as much (more) than the next guy but it will never look like an optical filter. Besides, Alchemy is not a mist filter. It only affects contrast.

 

[Tim Sutherland]

The other thing about stacking filters is that you might possibly get some double reflections especially with any bright practicals in frame.

Otherwise we stack soft fx filters all the time to get the right amount of diffusion.

Tim