D800 Autofocus Repair Testing

[box type=”info”]Update April 1, 2013: Testing after the second repair attempt by Nikon is now online here: https://photokaz.com/2013/04/nikon-d800-autofocus-repair-testing-the-sequel/[/box]

[box type=”info”]Update January 20, 2013: Initial testing showed changes to the focus performance and I thought the slight softness in some shots could be fixed with fine tuning. After more testing, I could not get consistently sharp results from fine tuning. I had to set my fine tuning for the Nikkor 24-70 f/2.8 lens to +20 and that still didn’t result in good performance. My AFS 50mm f/1.8 and AFD 80-200 f/2.8 lenses also had to have +20 of fine tuning. I dropped off my camera and the three lenses with Nikon last week, told them the problems and said I wanted everything repaired. I will once again post my results when I get the camera back.[/box]

[box type=”info”]Update February 9, 2013: Got my camera back from Nikon, still waiting for my 24-70 lens. Some testing with the 50mm f/1.8G using FocusTune is not looking promising :([/box]

I made a previous post about the issues my Nikon D800 had with phase detect autofocus, my test charts clearly showed a problem with the left side AF sensors.  I dropped off my camera at Nikon and it came back with the following info.



Service Repair Rank B2








So it looks like Nikon actually did make a fix, though I have heard some people had cameras returned with B1 service repair but I’m not sure how they differ.  Today I decided to do some testing on the ‘fixed’ camera to see if it was any better.  Same test procedure as before, same Siemens Star test chart.  I only tested the 24-70mm f/2.8 lens as that more obviously showed the problems before.   Below you can see the results for the lens at 24mm, ISO 100.  Top row is Live View manual focus (reference), next is Live View autofocus (to test contrast detect AF), then two rows viewfinder (phase detect) autofocus tests.  The VF AF 1 is racking focus to the closest setting before letting autofocus take over, VF AF 2 was a rack to infinity.

Nikon D800 Post Fix Test - 24-70 f/2.8 @ f/2.8, ISO 100, 24mm


Disregard the differences in white balance, the right test chart was closer to a different set of lights. Focus should not be affected overall, and shows relatively consistent operation left, center, and right.


I repeated the test at 70mm but this time didn’t test Live View autofocus. Here are the results.
Nikon D800 Post Fix Test - 24-70 f/2.8 @ f/2.8, ISO 100, 70mm


As before focus looks to be consistent, if not perfect, between the three tested points.


Finally, putting together my previous test charts with the updated tests shot today. Top row is Live View manual for reference, next row is the viewfinder autofocus tests before the fix and third row are the tests after the fix. This should clearly show that the fix worked. One thing to note is that the autofocus, even after the fix, is not in perfect focus however I hope that autofocus fine tune can fix that.
Nikon D800 Pre VS Post Fix Test - 24-70 f/2.8 @ f/2.8, ISO 100, 24mm