D800 Left AF UK repair experience

Started Feb 27, 2013 | Discussions thread
OP McKie Forum Member • Posts: 92
Re: Or does it

Leonard Shepherd wrote:

McKie wrote:

Hi Leonard,

I didn't post the pictures but if I had you would have seen that the viewfinder's right AF sensor was as accurate as the live view in my tests. I got sharp photos of the test charts using the viewfinder's centre and right AF sensors. To me that shows there is something up with the left AF - the right can handle it but the left can't - why would that be?

First apologies for mistaking the image as yours.

Second a few have reported good left autofocus and poor right autofocus.

Checking where autofocus can actually detect detail shows the extreme outer points detect vertical detail only (as most know) slightly inside of the position of the other vertical reading line detectors.

Using the letter F as a subject neither side is likely to focus good if covering only the vertical part of letter F. If lined up slightly to the right of the letter F the left AF can usually focus the horizontal direction parts of the letter, and the right cannot. Reverse the F, line up slightly to the left and the right can usually focus and the left cannot.

This autofocus idiosyncrasy applies to the D3s and D7000 as well as the D800.

One the challenges in determining if there really is a left/right autofocus issue is, so far on this forum I have seen 123 links to images similar to the one I mistook as yours, where Nikon caution autofocus may not work accurate. I have seen no images which seem to follow Nikon's guidance.

I accept there maybe the odd problem camera. With 123 on this forum appearing not to test to a satisfactory standard to reach a fair conclusion, and those testing to a good standard finding no fault, it does seem a major issue might be a small but vociferous group of posters reaching a conclusion based on less than ideal testing.

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Leonard Shepherd
Many problems turn out to be a lack of intimate knowledge of complex modern camera equipment.

Hi Leonard

You've misunderstood me or I wasn't clear enough.  I did post the target pictures of the problem I'm having with the viewfiner left AF sensor.  What I was trying to say was if you saw (which I haven't posted) the exact same target taken with the right AF sensor the image is sharp.

So my question still is why should it work with the right AF sensor and not the left AF sensor when the target and conditions are the same.  On my camera this is not an isolated example.  The left AF sensor always has a problem with wider angles and wider apertures.  I've used enough Nikon bodies over the years to realise something is wrong.

So why the inconsistency between left and right if it's not an AF sensor problem?


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