16 Sep 2012

D800E - autofocus issue: confirmed after the tests

As mentioned in previous post, I suspected that my D800E might have an autofocus issue when using autofocus points located at the left side of the viewfinder. I have decided then to perform more thorough test to see if the issue is real. I can say that there is a problem with my camera (left focus points don't work well, but on the right side the results are not so great as well). If one is interested in the technicalities of the test, read on.
The test I have conducted is based on the setup as described by Nasim Mansurov on his blog here and here.
It is pointless to repeat the test procedure in my post. So let me point out just a few aspects I have gone through when testing my camera:

Test approaching the autofocus point from both sides (low and high distances)

It means that for a given focus point I did two tests. I made the exposure initially unsharp by setting the lowest available distance for the given lens. So I turned the lens focus ring manually to the lowest possible distance and did the test. Then I turned the focus ring to infinity and redo the test again.
Why is it important? It turned that for both lenses I have tested, my D800E performs better when setting autofocus starting from low distances. When the exposure distance of a lens was set up to infinity, the autofocus performance was much worse (i.e. the autofocus didn't work). 
So by taking only one side one might not notice the problem.


Speed up the test by using tethered mode

I have connected my camera to the laptop and to 40'' TV set to see the results in a big format. Tethered mode for D800 is available in Adobe Lightroom 4.2. It is not officially released yet, but the release candidate version works pretty nice.  Having the results immediately on the big screen speeds up the procedure

So, what's next?

I have contacted Nikon Netherlands and they are aware of the issue (as a matter of fact they expect quite some more calls with respect to the issue). They claim to be able to fix it in one week. Let's see.