p.1 #1Sigma 20-200mm Lens vignetting with 7nmm Filters
Just bought the Sigma 20-200mm. I am intending to buy filters for this lens, especially a magnetic polarizer. I know the filter size is 72mm. Do you think when using 72 mm filters, that I will get additional vignetting from them, especially at wider focal lengths? Should I buy a larger filter size and use a step up ring to decrease potential additional vignetting from the filter? I know there is quite a bit of vignetting at 20mm wide open, but I intend to stop down most of the of the time with this lens and correct vignetting in Lightroom.
p.1 #2Sigma 20-200mm Lens vignetting with 7nmm Filters
No specific experience with that lens. But I am thinking Sigma engineered the lens so that a filter using the provided threads will not cause vignette. I would feel comfortable using a single filter of typical width. If you want to stack multiple filters then a step up seems reasonable.
p.1 #4Sigma 20-200mm Lens vignetting with 7nmm Filters
I have a tiffen cpl on my sigma 20-200 and I don't know the exact thickness, but it's thicker than my other magnetic urth filters and I haven't noticed any vignetting at 20mm. I suspect it would definitely vignette with 2 filters though.