Originally posted by Mike L How do the filters perform when using a lens with a 77mm filter size at the wide end, say 16mm or 17mm focal length? Any vignetting or other issues?
I have the same system, so I'll step in and answer this question and go a little bit deeper.
With the normal Cokin holder and a Sigma 17-50, you have to get it
just right for the holder to not show up in the corners. Using an APS-C 16mm with 77mm filter threads, the holder shows in all 4 corners.
HOWEVER - you can buy an extra $26 Cokin BPW400 wide angle filter holder for your wide's. It's a single-slot filter holder, and that will take lenses as wide as 20mm on full frame (77mm filter threads again) without showing signs of the holder. A 19mm lens or wider on FF will show the Cokin frame on the edges.
I am fairly alarmed that I have enough lenses at these focal lengths and filter thread diameters to confirm all of these tests.