I am currently using a cokin P system on my 5dii with 24-105. I am using the wide angle adapter piece to hold the filters and I still get slight vignetting at 24mm. I then tried the 24-105 at 24mm on my crop camera and there was no vignetting. I am wanting to buy an UWA either a 17-40 for the 5dii or 10-22 for my crop camera. I was wondering which lens will show more vignetting when using this Cokin P system. I am imagining it might be worse with the L lens because of the larger sensor picking up more of the corners/edges. But then again 10mm is a lot wider than 17 so wondering if that would negate the less vignetting effect I had experienced with my 24-105. I hope to hear from someone with experience using wide angles on both formats.
FWIIW: Cokin has a slim P filter holder with only one filter slot, and it seems to work fine (no hard vignetting; "soft" vignetting quite moderate if any) on my 16-35 from about 20mm on FF. The fact that there is no adapter ring (the lens has 82mm thread and takes the filter holder "directly") may be a factor. I expected it to do a bit better than that, because the front element is much smaller than the filter thread, but no, it vignettes below 20mm without fail.
The Cokin Z-Pro system is the next-largest size, and uses 100 mm filters. Note that the risk of vignetting is different for different lenses, independent of the focal length, so it is difficult to make generalizations based on focal length alone. The holder itself does not vignette, but the stacked slot holders on the side can catch the corners. I found that on APS-C the Canon 10-22 was good down to 11 mm, and the soft vignetting wasn't necessarily objectionable at 10 mm. On full frame, I've found that the 17-40 vignettes at about 17-18. On the Z-Pro the filter slots are removable, so if you take off one or two of them, vignetting can be avoided for most lenses.
Yea, currently the z-pro is not in the options for me. I am however, using the slim filter holder made especially for wide angle lenses with the single filter slot and still get soft vignetting at 24mm with the 24-105L. I wonder how much cutting or grinding off the plastic would cure the vignetting. I stuck my finger at the corner point of the source of vignetting and found that the plastic is a still a little high and I'm guessing that's what's causing the vignetting. I just don't have the dremel tools and such to make such a fine, clean cut. Does anyone have a sample photo of what the cokin p looks like at 17or 18mm? i can only imagine the vignetting to get worse from 24mm.
