There was a similar post on one of the forums recently. Many (including me) expressed the opinion that the 20/2.8AF is not outstanding on high rez FF bodies.
I would put that much $'s to one of the good zooms.
Yes, the 20/2.8D is not outstanding, but it's pretty sharp in the center wide open and the borders/corners get very good when stopped down.
It all depends on how you want to use it. If you need super sharpness from corner to corner then this is not the lens for you. If you want very decent sharpness stopped down a bit (f/5.6) then this will do just fine.
Though my 17-35AFS is a better 20mm in all regards, my 20/2.8D can't be beat for size/weight/cost and is still around for those times when a heavier alternative won't be taken along.
I just happened to be testing this lens on my D800e the other day. This is the 20mm AF f/2.8 non-D version.
I agreed with John, it is not a very good lens for the corners wide open. I think it needs like a f/5.6 to even be acceptable. The center, however is sharp.
These test are handheld, one was in the car and the other in the living room. Just converted to JPEG, no sharpening applie.
