After two trips to Nikon to fix the left focus issue between July and October the camera is focusing worse than ever. (There was a delay between trip one and trip two while Nikon Japan pondered the situation. For me, the story that this problem is fixed is not proving true.
I have uploaded samples to Osthus.us/focus_test.
If you decide to have a look and help me out with your insights, you will find a big zip with about 20 images. I have also uploaded a few sample JPEGs of some of the worst examples for anybody who does not want to download the big file to see the test series.
Test conditions: Tripod mounted. High shutter speed. Defocus then focus via left, center then right sensors. The photos of my 85 mm 1.4 were hand-held.
In the zip file you will see a couple of series of 3 shots where the target (mailbox) is centered in each of the three images. What I did there is shoot left-sensor focus, lock and re-center, center sensor; then right sensor focus, lock and recenter. This was done to give me three shots with the target centered. For good measure I simply shot left, center and right sensor images of the same target.
What I see:
-There is variation in focus across all sensors - The image sets where all three shots were framed the same show a large variation in file size. In some cases as much as 2 MB with the SAME SHOT.
I also tied normal shots like focusing on a red barn isolated against a blue sky; and the D800 could not reliably hit the side of the barn.
I would be grateful your insights. Do I really have a focus problem or am I imagining this?