Distagon 50/4 stopped down to f/11 or f/16. Keep in mind that the JPEG images are sharpened. Best to download raw image and check yourself.
My impression is that the lenses I have are decently sharp, with reservations about the 120/4 Macro Planar when used at infinity.
I have also bought a 40/4 FLE (still waiting for it). A very good friend of mine has a 250/5.6 Sonnar I can test in a couple of weeks.
Thanks for showing this. For a guy who perhaps wanted to upgrade this could be very intersting.
But one question from me:
Which lens had you used for this picture: 20130626-CF043214.iiq ?
It seems to be very sharp.