I'm looking for an ultra-wide angle lens to use with my Olympus OM-D E-M5. I've tried out the native Panny 7-14, but it's a bit too pricey for me. The Samyang fisheye was also recommended to me, but I think that I'd prefer something rectilinear instead. I want something wider than the Oly 12-50 kit lens that I already own, but don't see any other native lens choices at this time. That got me to thinking that perhaps there's an adapted lens out there that might do the trick? I have the Cowboy Studios Nikon-mu43 adapter, so a legacy Nikon would fit the bill. But I'm not eliminating other manufacturers (although I'd need a link to the right adapter to get for it). Prime or zoom -- doesn't matter to me. So, does anyone have any recommendations for a UWA adapted lens for use with a mu43 camera? And are there any drawbacks to this strategy? Thanks!