Strong neutral density filter tips?

NHBubba

So I recently got myself a strong (10 stop B+W ND 110) neutral density filter. I bought it for landscapes including water. I want to use it to smooth out ripples, waves, or spray in moving water.. pretty much what you'd expect. I've used 1 and 2 stop ND's before w/ some modest success. But this 10 stop is a whole different animal! Can anyone offer any tips or tricks for getting good results w/ it?

For starters my camera can't seem to meter through it to save it's life. Shots are always way too dark. Do you meter w/o and then do the math and shoot in manual mode? To be fair, all my testing so far has been on relatively overcast days. Bright sunlight has been in rather short supply lately. Does this issue go away in direct sunlight?

How about focussing.. do you trust auto focus through the filter? Or do you set and lock the focus w/o the filter?

How about vignetting/falloff. I am very interested in wide angle landscapes. I bought the filter in 77mm size to fit my sparkly new 10-22 ultra wide.. but it seems to give some falloff. My local scientist/optical expert explained why this is (compete w/ diagrams!). But is there any tips on how I can minimize the effect? He suggests shooting at greater f-stops. Is this normally compensated for in post-process?

Thanks..
-Colin

Mike Bell

NHBubba wrote:

How about vignetting/falloff. I am very interested in wide angle landscapes. I bought the filter in 77mm size to fit my sparkly new 10-22 ultra wide.. but it seems to give some falloff. My local scientist/optical expert explained why this is (compete w/ diagrams!). But is there any tips on how I can minimize the effect? He suggests shooting at greater f-stops. Is this normally compensated for in post-process?

Thanks..
-Colin

I have been researching filters for my new 10-22 lens. Canon and some posters in forums (see the sticky in EF lenses at http://photography-on-the.net/forums ) advise paying premium prices for ultra-thin filters for this lens. Others say you can get away with one normal thickness filter. So I have ordered a standard one and intend to try it in the shop before I buy. I rarely use it at its widest anyway!

pathfinder

I focus and meter through my ND filters routinely - But my densest is 8x, I believe. 10X is really dark - hard to see through.

Lots of sunlight will help of course, as will f2.8 or faster primes. F4 or slower lenses will have to work much harder to meter and focus. In dim light all metering and focusing will have to be done before applying the filter.

Thinner mounting rings and thinner filters are used by some folks to help prevent vingetting with ultrawide lenses. I think if I really saw that in the viewfinder I might try a pano of two frames with a slightly less wide lens to avoid the issue for stationary landscapes myself.

David_S85

If your in-camera meter can't read well through the 10-stop filter, you could always meter first without the filter (writing down the settings), park the cam in manual, and figure the stops backward then set the cam to whatever that comes to.

NHBubba

Hmm.. I really don't think what I'm seeing is vignetting in the typical sense. That is I don't think it's the filter ring that's causing the fall off. One of our staff is pretty knowledgable about optics and he explained that because w/ an ultra wide light is passing through the filter at a very low angle relative to the axis of the lens, the light actually travels through more glass and hence the effect is effectively more than 10-stops at the edges. His suggestion was to use a smaller aperture.

So I tried this. Yesterday I took a bunch of shots in bright sunlight (or at least the brightest I could get for this time of the year) at various stops from f/4 all the way down to f/22. My test wasn't all that scientific.. but I definitely could tell the falloff was less at f/8 than it was at f/4. Ultra wides suffer from falloff wide open, apparently the ND just makes this much more pronounced. Going from f/8 to f/11 or f/16 doesn't seem to improve things much though.

So I guess that's part of the solution: don't use less than say f/8. Not that that's a problem.. I bought the filter to slow the shutter. I never expected to use it w/ the lens wide open..

The metering is a bit of a shock though. The same camera/lens combo meters well at night and indoors in low light.. I don't really understand why it's so off outdoors w/ this filter. But using the 'sunny-16' rule and compensating in my head seemed to work well. I guess that's just what I've gotta do..

Still.. maybe a 10-stop is too much. Maybe a 6-stop would have been a better investment. I just didn't ever want to get into a situation where I'd have to go stacking filters on this ultra-wide.

wxwax

Good stuff, Bubba. I especially like the explanation for the vignetting. And of course, your excellent point that when shooting with an ND filter, you shouldn't be wide open anyway.