ND Filter - What Speed, which one?

[J.F.R.]

Coming from video cameras I never really grasped the whole ND speed thing as they were always there, but now with DSLR it is different. My question is this.....

What ND do I need to be able to shoot with a lens wide open at 50 shutter speed? I seen there is variable and fixed ones, but really don't know which one is best. I also have a matte box but in many run and gun shoots it's just not practical.

Also I seen there is .3,.6,.9 then these is ND4,ND8 etc. Which is which and what are the different ratings?

Help me out as I need to buy one asap
thanks

 

[Samuel H]

On a bright day, at ISO 100, f/2.8 and 1/50s, I usually need 6 stops of ND filtering to get good exposure (maybe 7 if it is VERY bright, or if I want to bring the sky down a bit).

So the most useful kit for me is 0.6 0.9 1.2 (since stacking doesn't seem to be a problem on my cheap Tiffen ND filters).
I think it's this one: http://www.amazon.com/dp/B003AV3HPG...www.similaar.com/foto/equipment/us_video.html

The meaning of all those different scales is here: http://www.similaar.com/foto/tuten/630.html

 

[drapeama]

So the most useful kit for me is 0.6 0.9 1.2 (since stacking doesn't seem to be a problem on my cheap Tiffen ND filters).

I have the same set of ND filters, 4x4 from Cavision (Glass filters) and I must admit that it's a very nice set of glass filters for the price. I'd recommend it to many people that are building a starter kit.

 

[c3hammer]

I have a bunch of Hoya ND's. I was able to test different combinations at our local camera store and found that it takes one ND-4 and a circular polarizer to get to f/4 and two ND-4's to get to f/2.8 in broad daylight on my T3i. For snow or white concrete it takes all three to get to f/4. If you want to get to f/1.8 you will need at least an ND-8 and an ND-4 in mid day sun. Add anything bright in that mid day sun and you'll need even more. Maybe even two ND-8's.

I don't know how that compares to other scales, but should give you an idea of how the Hoya numbers work at iso 100 and 1/50th of a second shutter on my dslr.

Cheers,
Pete