Sat 01-Sep-12 02:56 PM | edited Sat 01-Sep-12 02:59 PM by Ferguson
One of the links above was mine, and I was having serious issues with my 85/1.4G on the D800.
I had the left focus repaired, and things are MUCH better now, in a way not really expected.
Prior to the repair, up close, it required a positive AF of about 2, but at distance it required an AF of -10. There was no happy medium, and if tuned to either of those, when shooting at the other distance was soft.
After the repair there's still a difference (about 18 to 6) but at a compromise point there's no significant softness at either focus distance. Yes I realize both span 12, but the slope of the curves is different now, and up close doesn't (now) get bad as quickly as you move out from the peak AF.
While I have little real life experience with it since repair (only had it back a week), I think the repair has solved my 85/1.4G problem.
Oh... and in the meantime I bought a D4, and it works quite well there. But even there there is a significant difference in AF fine tune needed at distance vs. up close. But again, there's a happy medium that takes the difference below noticeable.
I had been thinking about dumping it, but now am happy with it. Amazing what a reasonably unrelated repair will fix. And the brokeah is just terrific on the lens, as well as the edge to edge sharpness when you do get focus correct.
(That's a D4, since my D800 was in the shop at the time)
I have recently seen the phrase used a lot "Low tolerance photography" and that is a good definition of the D800 and 85/1.4G. There are more ways to screw it up than get it right, but when it is right, it is terrific. I printed the curves at different distances, and if I REALLY want good results I will likely use live view, and if I can't, will set the AF for a specific distance. Not normally, but with fractions of an inch of DOF at times, there really are low tolerances.