Hate to admit it, but I have the AF issue. Going to make a case with Nikon. Any advice?

Started Nov 4, 2012 | Discussions thread
Fayard
Regular MemberPosts: 127
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Re: A reminder
In reply to Marc Heijligers, Nov 8, 2012

Marc Heijligers wrote:

Leonard Shepherd wrote:

While you are at it, try finding a link at dpreview showing an AF fault using a sensible for testing AF subject. I might have missed one - so far I make it 87 to nil did not use a sensible AF target.

You did not miss one, you've missed about 87.

Here is another on he might miss.

These pictures were shot with my D800 and my AFS 85mm 1.8 lens. The aperture was set to 1.8, the focusing distance is 2.5 meters and the focus was made on the concentric circles on the box (upper left side of the crops). The AF Fine Tune was adjusted to -2 so that the central AF sensor is fine tuned. You can easily check the ground to know where the focus has landed.

A first 100% crop, focused with the central AF sensor to check that my AF Fine Tune is correct. As you can see, this image is perfectly focused.

Another 100% crop, focused with the left AF sensor that shows a clear backfocus of about 10cm.

If you are not convinced, let's try with another lens. An AFS 35mm f1.4. This time the focus is made on the sign and you can use the ground to check where the focus has landed. The focusing distance is about 2 meters, the aperture 1.4 and the lens has been fine tuned for the center as you can see with this first image focused with the middle AF sensor. Everything is fine.

With the left AF sensor, you can clearly see a backfocus.

and if you are interested, the right sensor does front focus.

One last example, with the AFD 105mm f2.8. Again, focusing distance is 3 meters, the lens is fine tuned for the central AF sensor, the aperture is f2.8 and I do focus on the central concentric circles. First, a picture with the central AF sensor to prove that the lens is fine tuned:

and then a nice backfocus with the left AF sensor

And you can try those test (I've done it) with different targets (Horizontal black and white stripes as can be seen on Thom Hogan's website, USAF charts, barcode), my D800 will always give me the same results.

I am ready to talk about the fact that it is something we have to live with, and that my D800 is "within the D800 specifications" . I've tested 3 D800 this summer and they all lead to the same results. I've also tested a D600, and there was also some misalignment but it was not that bad.

If you want to download all the pictures and check the EXIF, they are available here .

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