Nikon D200 + 70-200mm f/2.8 @ 200mm — ¹/350 sec, f/2.8, ISO 400 — full exif
Autofocus Doesn't Get Much Better Than This
The up/down range of what's in focus is indeed centered on the focus point

As I mentioned the other day, my camera was in the shop to repair poor autofocus. It's back now, and my first quick tests show that its autofocus is now excellent.

I'd first run into problems with the Nikon 70-200 f/2.8 that I got in November. I posted about it on the Nikon SLR Lens forum on Phil Askey's Digital Photography Review (this thread) and was told that the problem could well be my fault for not understanding what I should expect from the autofocus system. In hindsight, considering the test photos I sent, those comments were fair. So, I went about testing with a focus test chart that I designed myself, and confirmed that indeed the equipment was having issues. So, I brought it to Nikon, and after inspecting it out for three hours, they accepted it for repair.

That Nikon accepted it for repair made me feel a bit vindicated, because there are those that reflexively accuse “it's your poor technique” whenever someone suspects a focus issue, never allowing that someone might indeed have faulty equipment. In particular, one loud mouth active in these forums, Leonard Shepherd, was incessant in his accusations of ineptness to everyone (including me), even in the face of clear evidence that the person he's accusing understands the issues well.

The feeling of vindication was short-lived, because unfortunately, the situation was worse when I got the equipment back from Nikon.

I think I pretty much understood the problem early on: the 70-200 zoom needed to be calibrated. What Nikon did was adjust my D200 body to match the miscalibration of the 70-200 zoom, rendering the body miscalibrated for any other lens. Sigh. Was I being unreasonable for wanting good autofocus?

I do expect equipment at this level to work, so I had to send it in again, this time with more explicit instructions. That I have to explain camera repair to Nikon is well beyond my understanding, but it seems to have done the trick.

So, I got it back yesterday, and today did a few quick test shots with my pro glass, the 70-200/2.8 and the 17-55/2.8, and found autofocus to be excellent.

So, what did Nikon do this time? Here are the reports....

For the D200 body:

For the 70-200 f/2.8 zoom lens:

I'm not sure what they're talking about in the second line, since I never mentioned anything about the “resolving power,” and indeed there's nothing about it in the “customer's complaint” part of the form (the whole thing of which you can see if you click on the snippet shown here.) In any case, I'm glad things are fine with it.

For the 17-55 f/2.8 zoom lens:

Which is what I expected: the problem was with the 70-200, and, after Nikon's first “fix,” with the body as well. (For those keeping score, the report for the 18-200/VR was similar to the 17-55/2.8)

In Summary

In summary, I was right all along: the 70-200 was miscalibrated, and it took Nikon two tries to get it right. I didn't realize that there was anything initially wrong with the D200 body, but perhaps that's because my only lens before, the 18-200 f/3.5, is too slow to reveal the problem.

In any case, I'll take everything out for some real-world tests the first chance I get, but at this point I'm pleased that things finally seem to be fixed.