I have recently purchased a Cokin Z-Pro system, but I have not yet tried it that much - I've been much too busy. Cokin states that it should not vignette on 20mm or longer lenses on full frame - and just like they said - on my 16-35 it only vignettes wider than 20mm. (However - you can reverse the holder and thus reduce the vignetting at wide focal lengths, although you'll only fit a single filter.


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If you buy it - go for a U960 kit - with the holder, three ND grad filters and a nice, large filter pouch. The holder will take any filters 10cm (4") wide - Cokin, Lee, Singh-Ray, whatever..