Nex 7 + CV 15mm questions

I had one of these and loved it on my nex-5n.

By comparison poor on the 7 - very bad magenta cast, very bad vignetting, blurred corners that only get a bit better at higher apertures. All in all pretty useless on the nex-7.
Corenrfix doesn't work miracles and is only for RAW.

On a side note the CV 25mm is better on the 7 with only light magenta issues in the corners and much less blurring in the corners.

Regards
Glen Wells