Has anyone used an aftermarket 58/77 step up ring for the slr magic hyperprime 12mm lens? I'm getting the lens soon and don't really want to spend $80 + shipping for their proprietary ring.
Clearly there are lots of cheapies and Heliopan makes a thin brass version (still pricey @ $47) but I'm not sure if it's worth it either. I just want to make sure that the ring I get won't cause vignetting with an added filter (ND or other) without paying the crazy premium for the slr magic ring.
Any advice?