In my test shootout I found the CV has a fair amount of CA. Less than the 21 Lux, but more than the slower 21s in the comparison. The CA cleans up pretty well in LR. It will purple fringe somewhat in high contrast situations at wider apertures, i.e. backlit tree branches. On the whole though, I think it's a great lens that effectively balances speed and optical performance for the price.
My 21/1.8 arrived today. No color shift on the 5N... technically speaking there's a tiny bit there, but I'm not seeing it unless I go hunting for it with some hard adjustments to saturation sliders.
I've been housebound with my son due to having my truck in the shop today, so no walkabout yet, but I'm going to be taking it snow camping with me this weekend. That should be the telling test. I'll have some shots to post when I return
