How to buy an ND Filter

I'm looking to buy an ND filter for use with my 6D. I was out testing today on a bright afternoon and noticed that with my 50mm f1.4, I hit my max shutter speed (1/4000) at f.2.8, I believe.

I'd like to get a filter that will allow my to go wide open with that lens (1.4). How much do I need and what do the numbers next to the filters mean?

For instance, looking on Amazon I see something like - "Neutral Density 0.6 filter". Does 0.6 = 6 stops? I'm confused.

Any help would be appreciated.

0.3 = 1 stop = ND2
0.6 = 2 stops = ND4
0.9 = 3 stops = ND8

There's a good chart here: http://en.wikipedia.or​g/wiki/Neutral_density​_filter

Look for Marumi, Hoya and B+W if you're going for a screw-in filter solution; and, Cokin or Lee if you're looking for a "panel" filter solution.

Thanks for that link, that's exactly what I am looking for. I'm wondering if a 3-stop filter would be enough, or if I should just go for more?

Do you care if your shutter speed remains high? If not, I'd start with a 3-stop. I find that to be a good balance for general use (portraiture, narrow aperture longer exposures). Under the same lighting conditions you had, a 3-stop would let you shoot wide open at 1/2000.

I'm not too concerned about high shutter speed. I'm more interested in shallow DOF portraits in bright days. I think a 3-stop is a good start and I can go bigger from there if I find I need to slow down my shutter even more.

3 stop is a good starting point, for sure.

Steve, I hope you don't mind if I tag along. I'm also looking to get an ND filter. Will a 3 or 4 stop filter cause AF problem? (for example, shooting at noon on a sunny day). Just like OP, I'd like to use this filter so I can shoot at larger aperture (shallow DOF) and my max shutter is 1/4000.

Is thisgood?

I personally don't have issues with AF until 6-stops. But that is in good strong light and not trying to track motion. That Hoya would be fine, and Marumi makes nice ones as well which are less expensive. No 4-stop though. Only 3-stop.

I bought a variable density filter and can adjust for conditions and desired effect.

This is not cheap, but proportionally costly to your nice Lens. Should give good flexibility to value for money.

http://singh-ray.com/varinduo.html

Thanks Neil. That's good to know. Southern California sun can be blinding sometimes. I'm often shooting around 2-3 pm in bright daylight. I need some filter to block the light.

I heard variable density ND on a UWA lens might cause an X mark on the picture. Since I'm going to use this 77mm filter with my 11-16mm lens (as well as other lenses + step up/down ring), I'm afraid var ND isn't a good choice. Oh... that Singh Ray filters... waaay out of my budget. That would be something nice to have if I won CA lottery.

morph2_7 wrote in post #15770076
I heard variable density ND on a UWA lens might cause an X mark on the picture.

You heard correct. One of the reasons I never use mine. It's also impossible to accurately know just how dense it is set. Which makes exposure calculations impossible - you need to try it and see.