Thu 05-Sep-13 02:42 AM | edited Thu 05-Sep-13 02:43 AM by Ferguson
>Still a newbie at this. How did you determine that the far >left sensor was not working? >
I'm not Eric but I'm waiting for a bunch of shots to download...
Google "D800 Left Focus" and watch the number of hits.
More seriously - mount the camera on a tripod, and pick a very good focus target (read in the manual about what makes a good target). Ideally get three of them that are identical, and put them on a flat wall perpendicular to the field of view of the camera. Be sure they are at the same height as the camera.
Place them very carefully so that the center one is in the center focus point, and the left-most and right-most point have the other two.
Set the camera for "A", AFS-S, lock down the tripod, set exposure delay to 3 seconds.
Take several exposures using each of the three focus points. Each time defocus manually, and let the camera automatically focus. Take several to see if there is variation.
Now go into live view mode, and set focus to manual. Zoom in very close (usually max less 1 or 2 zooms). Focus VERY carefully, get the absolute best focus. Do this on all three focus points. Do it several times each.
Now compare your results. The NORMAL results is that the center done with auto-focus is almost but probably not quite as good as live view, and that the left and right are each yet more soft relative to live view, but still decent.
If all three in auto-mode are much more soft than in live view, you need to fine tune, then start over. Back/front focus is a whole different topic, search for "Fine tune Nikon back focus".
The LEFT FOCUS problem will show up as the automatic focus on the left side is VERY soft, while the right side is slightly softer than the center, but much better than the left.
Now repeat this with some different targets and if you have them, another lens or two.
Optionally, post your results in several online forum, and collect a half dozen followers who will tell you (a) you are crazy, (b) Nikon is involved in a conspiracy, and (c) your focus target does not meet the criteria for the AF system to work. These three things will happen no matter how you do your testing.
If your camera consistently is very soft on the left -- you have the problem.
If left and right are more or less the same, you don't.
If all three are pretty much in focus in both live view and manual, you have great luck. Post your results in several forums, and (a), (b) and (c) above will still happen.
But seriously -- that sounds complicated but it is not -- you need to compare to live view as that's the gold standard, and the "problem" is when in AF mode (not live view manual focus) only the left is really soft, you have the issue.