ND filter

[Phenix205]

Hello, all. Looking for an ND filter. I heard that for using fast primes (faster than f1.4) in sunlight, a 3-stop ND is ideal, but for waterfalls and moving clouds, a 9- to 10-stop is better. Any advice on which one to get? Thanks.

[neuroanatomist]

Well...are you planning to shoot outdoor portraits with a fast prime, or waterfalls and clouds?   

Personally, I think 9-10 stops is a bit dark for waterfalls, but good for clouds and 'removing' people from architectural shots.  3-6 stops work well for waterfalls - personally, I often use a 3-stop with a CPL stacked on (meaning ~4.75 stops of darkening).  So, I have both 3-stop and 10-stop filters.

[Random Orbits]

Depending on the lens focal length, you might be able to get away with a variable ND filter.  At about 24mm, I was getting about 2-3 stops shooting into the sky.  At about 200mm, I can get about 8 stops with the Schneider.

[Phenix205]

Thank you neuro. I agree that 9-stop may be too dark for waterfall as water moves pretty fast. All my lenses are f2.8 except the 50 f1.4. Maybe I should start with a 6-stop, then add a 3-stop later as needed?

[Razor2012]

I just picked up the Lee filter system with a Big Stopper (10 stops).  You can get 3, 6 and 9 stops also.  This is a great because all you have to do is buy different size adapter rings for your lenses.  I plan on getting some colored grads too.

[scrappydog]

I agree with Neuro that 10 stops is overkill for a waterfall and that 3-6 stops should do you fine.  Below is a link to a shot of a steam that I took with a 10 stop -- the exposure time was brutal (something like 2-3 minutes).  You can get the same effect with a lot less waiting around.

http://www.flickr.com/photos/68498746@N08/6290310018/#in/set-72157628000165436

[TexPhoto]

And don't forget, you are usually shooting a waterfall with a small aperture, f11-f22, to maximize depth of field. So the 3 stop is likely plenty.