Final observations on D800 AF repair

1. Introduction

After the repair of my D800 autofocus, it turned out that my 14-24mm/f2.8 lens was still not working correctly. The lens was giving good results at 24mm, but at 14mm it was only sharp using the left AF field. When calling the Nikon Service Point in the Netherlands, they advised me to bring my camera and lens for repair. Nikon has the possibility to AF fine-tune the lens relatively shifting the 14mm focus to the 24mm. They also asked me to bring my 24-70mm, as it is known for the similar problems.  

2. Results after repair

My 24-70mm/f2.8 was considered to be an extremely good copy, and hence was not touched. The 14-24mm/f2.8 was investigated, and indeed some issues were found. It was corrected for front focus at 14mm. The technician did not completely optimize it for near-by focus, as otherwise the lens wouldn’t focus correctly for infinity anymore. So trade-off performance is to be expected. On the test card of NSP the focal results look good after the repair (click on the picture for an enlargement, all are 100% crops): 

left side 14mm/f2.8, right side 24mm/f2.8, left, middle and right AF fields from top-to-bottom (AF-fine tune +5): 

14 24 after

Hence, all looks OK! Checking the AF results with my book shelf also shows good results (left side life view, right side viewfinder), with some minor deviations, but this is within expected tolerances of AF accuracy and put correctly on the optical axis. 

24mm/f2.8 (AF-fine tune +5): 

14 24 at 14 2nd

14mm/f2.8 (AF-fine tune +5):  

14 24 at 14 2nd

I’ve also checked the lens for AF at infinity. At 24mm the results are good, at 14mm these is a slight tendency to unsharpness when using  the left AF field. See underneath the difference for left, middle and right AF fields. For live view all AF fields are sharp, hence this shows there is still some offset w.r.t. mirror-based autofocus. 

14mm inf 600

When scaling down to D700 resolution, the differences are less noticeable:  

Screen Shot 2012 07 15 at 1 41 07 PM  

Please be aware this is pixel peeping, the overall picture is shown below:

DSC 1818

3. Overall conclusion

From a technical point of view the (repaired) D800 is still subject to asymmetrical AF variations (and maybe the ones that are reported to be without any problems may have some issues in these type of cases as well). Most autofocus use-cases do work correctly for me, with the exception of 14mm at infinity with left-field AF at significant magnification. This is a use-case I hardly use, so I’m fine with the current situation. 

Overall I’m satisfied with the current status of my D800, it allows me to take beautiful pictures with a lot of detail and headroom for post processing. Nevertheless, I don’t understand why Nikon is not capable of producing a 36 MPIx camera of €3000 with an AF mechanism that is not as precise as the one in the D700. For that reason, on a scale of 10, I will give my D800 a score of 8 to 8.5 instead of a 9.5 to 10. 

As for the repair, I’m very happy with the service provided, it is clear that the service centre has done everything that is possible. The fact that they’ve also serviced my 14-24 lens (and asking for the 24-70) gives them a 10 out of 10. 

This will be my last report on AF-testing (unless something significantly new pops up). I hope my writings gave some useful background info to you, and encourages people to send their camera (and lenses) for service, or give people the confidence to not hesitate to buy a D800 despite all the negative emotions out there. 

5 thoughts on “Final observations on D800 AF repair

  1. Great to hear, and thanks for keeping us updated.
    One small question about this calibration process that happens on lens. I presume that your copy of 14-24 worked fine on D700. Now that it’s adjusted to suit D800, will it pose an issue when you try to use it on D700 … In short, does lens calibration for a specific D800 affect it’s usability on other cameras where it used to work fine?

  2. Mike says:

    Thanks for your updated post, I appreciate it. I also sent my D800 for service in Canada and it came back working much better. I have some test charts posted if you or anyone else cares to see: http://photokaz.com/2012/08/d800-autofocus-repair-testing/

    I think everyone should test their D800 and send it in if they find a problem.

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