#2. "RE: Thom Hogan on the "Auto Focus Problem"" In response to Reply # 1 Wed 18-Jul-12 02:24 AM by mgd7
New York, US
Thanks for the link. It seems to be a pretty fair description of the problem based on what I've read and experienced first-hand. I sent my D800 to Nikon last week but did not contact them first as Thom suggest they would like (I didn't contact them first on either of the two lenses I sent to them for service this year, either. They have their SOP and I have mine.)
#4. "RE: Thom Hogan on the "Auto Focus Problem"" In response to Reply # 0 Tue 17-Jul-12 10:54 PM by JHzlwd
Thom does a good job prompting us to do some of our own tests and contribute constructive responses to problems.
For anyone interested I did my own "quicky" test for the left-side focus sensor problem and - sure enough - I have it. I prepared a rough web page with results and commentary. It should give visitors a reasonable example of what to expect.
#5. "RE: Thom Hogan on the "Auto Focus Problem"" In response to Reply # 4
Thanks for posting that link -- if the issue shows up any where near that dramatically I think my D800 is fine regarding the left sensor issue.
I still need to do some testing with better lighting, but what I've run so far shows a somewhat consistent (but small) difference between live mode and the the AF sensors across the line (left, center and right). BUT that difference is very small, and is not 100% repeatable (some images are pretty much right on); I really need to do it in better light. Some lenses did better than others, and the results weren't much different than what I got with my D7000 (in terms of comparisons between live view and the AF sensors). BTW: testing the D7000 actually confirmed a right-side (element alignment?) focus problem with my 18-200 that I had been suspecting (the right side of the images have seemed consistently soft lately); *that* piece of gear is at the service center now under warranty...
I also noted (and agreed with) Thom's point that it's too bad Nikon is forcing the customers to figure out if they have a problem or not -- it's a bit disappointing. But we'll see how this unfolds -- I anticipate they will get things right in the end, and they certainly seem to be willing to fix any problems that a customer does identify.
#7. "RE: Thom Hogan on the "Auto Focus Problem"" In response to Reply # 5
After Thom posted his suggestion on testing I decided to test my D800. It does have the problem, so I'll be taking it in for service.
I created a test chart as per Thom's suggestion, though I ran into problems. Contrast detect AF would not lock on the target, I'm not sure why but it could be because there were no vertical lines? This didn't happen every time, but it happened enough that it made the test difficult. Also, the horizontal lines made it more difficult to determine how out of focus the image was. For me, the Siemens Star worked a lot better.
I have posted the results of my testing with the 50mm f/1.8G and 24-70 f/2.8. The 24-70 shows the problem a lot more. I may also test with the 14-24 before I take it in for repair.