So I rebought the 55-210mm to use on my NEX-6 again, this time a somewhat better sample. I updated the firmware of the lens immediately to enable PDAF. And now I get erratic focussing, irrespective of whether I set the "Phase Detection AF Area" to On or Off in the menu. This is only logical as I have learned from another thread that this only makes the PDAF grid visible or not and that PDAF is always active. It looks like PDAF looks at a larger area than indicated by the focussing spot (I use flexible spot). In the example below I focussed on our dog's eye and the spot was completely filled with the dog's head. You can see that the photo albums behind are nice and sharp and the dog's head is not. Looking for a confirmation of this theory I did another test. First picture was taken at f/6.3, the second one at f/8. Both are focussed with the spot fully located within the lamp, incorporating the brown-to white transition in the bottom to have ample contrast for reliable focussing. I also switched Live View Display to On, which effectively takes care that the lens focusses at the aperture set, not its maximum aperture. And because PDAF only works at apertures of f/6.3 and larger (wider opening, smaller f-number), the lens uses PDAF for the first picture en CDAF for the second one. The first one at f/6.3. Lamp is not really sharp, optimum sharpness is somewhat behind. http://addieleman.smugmug.com/photos/i-hFxSfN6/0/XL/i-hFxSfN6-XL.jpg" > The second one at f/8. Lamp is as sharp as it gets. [img]http://addieleman.smugmug.com/photos/i-g7cPswS/0/XL/i-g7cPswS-XL.jpg It's a bit erratic, I feel like it's unpredictable where PDAF picks the target to focus on. I've done this testing after using the lens for a day or two and getting unexplainable focussing errors. The Sigma 30/2.8 and 19/2.8 behave perfectly as well as the Sony 10-18mm; the latter also uses PDAF but due its large depth-of-fields small errors apparently go unnoticed so I haven't these issues with the 10-18mm. Has anyone else discovered anything similar? Any known solutions? I'm pulling my hairs now that I've updated the lens' firmware, according to the Sony support pages there's no going back. I've read a very long thread on dpreview discussing these kind of issues with the 16-50mm on the NEX-6, pointing a bit in the same direction, although there didn't seem to be a conclusive insight. Please don't tell me to stop pixel-peeping or go take pictures or similar comments.