Upload & Sell: On
After having owned and used a Canon 50 1.2 for years, I sourced a CONTAX 50mm 1.4 N-EOS, converted by Conurus - so it auto focuses.
I sold the Canon.The CONTAX is hard to find, but they're out there.
Ultimately, for my uses, the lack of resolution out from the center resulted in my changing. The CONTAX (in case you don't know it is a Zeiss) is sharper edge to edge by a slim margin wide open, and by a larger margin stopped down.
I routinely shoot dance performances and often am asked to cover the full stage. 50mm is almost perfect for the distances being used, the scale of the places since there is little room to back up, etc.
I was unhappy, many times, with the detail other than the center and by the outer thirds I was very unhappy with the Canon. It's all about specific use cases, afterall. The Canon is a beautiful, dreamy lens but it is not very good if you use the full aspect, stopped or otherwise, unless you are seeking the edge softness.
So, with my 1DX, and previously a 1Ds M3, the CONTAX 50 1.4 is my most used lens for photo and videography.