Sigma SA lenses on A7/R through adapter
On Ebay I notice that Sigma SA to NEX adapters exist. I wonder how these adapters would work on my A7R. Given that Sigma SA is a crop format (relative to full frame), I assume that using such lenses as the Sigma 35mm 1.4 with such an adapter would result in vignetting.
Has anyone tried this combination? If so, what were your results?
Do the results vary depending on the SA lens being using?