I kept my old, NIB 50/1.4 and sold my battle-worn but reliable old one.
Silly me to do that without first testing the one in the box!
The new one has some strange behavior where it focuses perfectly, but only at certain distances, everywhere else it's either front or back focusing by as much as 2 feet at a 12 foot distance, for example.
This was tested using only center AF point on 3 different crop bodies, all with the same results and repeatable.
The old one nailed focus reliably, even if it did show a wee bit of focus shift when stopping down.
This newer lens is not even in the general vicinity most of the time.
Very disappointing and since it's well past warranty, I'm either fixing it myself or selling it. I need it to AF, MF not an option for my intended use.
Anyone else have a 50/1.4 USM behave like that and what was the specific fix?
Perhaps it's a position encoder on the drive train that's not working properly?
Edit - fixed many typos.