D800 focus with 1.4 prime lenses is very variable and inaccurate

Either it is really difficult to master, because after shooting tens of thousands of shots with this AF I still cannot predict when the AF works with 1.4 lenses and when not. 2.8 lenses work very fine!

Furthermore, after testing EOS 6D I can get very high accuracy with no experience with it at all!

Seriously though, Nikon's CAM3500 and it's versions are flawed with 1.4 lenses.

http://www.robgalbraith.com/bins/multi_page.asp?cid=7-12721-12406

" As of this writing, I've not sorted out why f/1.4 lenses seem to bring about poorer AF system performance with the D4, or if there is a magic combination of AF settings that might alleviate the problem. With this camera, like the D3S before it, I've sidestepped the matter entirely by focusing in Live View instead. This has been a manageable workaround, at least for static subjects, but it's not much of a long term solution."

ttp://diglloyd.com/blog/2012/20120811_2-NikonD800-autofocus-precison.html

"can I point a Nikon D800 + ƒ/1.4 prime at a subject at a moderate to far distance, hit the AF button and consistently get a sharply-focused image at ƒ/1.4 or ƒ/2? The answer is a resounding “NO”."

"Today’s tests with my factory serviced D800 and D800E + Nikon AF-S 85mm f/1.4G were a huge disappointment, showing me that using autofocus at a distance of ~80 feet is joke, showing hit and miss results ranging from sharp to soft to badly blurred. All on a tripod with everything fixed — just repeat the same thing and roll the dice on what you get. Which is entirely consistent with the numerous past tests with other Nikon bodies and other Nikon AF-S ƒ/1.4 lenses, which I’ve shown and proved over the years in my publications. The Emperor has no underwear."