My Lens Focus Issues Are Fixed, or “I Told You So”

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:

Nikon repair statement for my D200, in Japanese
Due to defective autofocus, replaced the autofocus unit.
Replaced the deformed lens mount.
Inspected the operation of all components.

For the 70-200 f/2.8 zoom lens:

Nikon repair statement for my Nikkor 70-200 f/2.8 zoom,
in Japanese
Report on the autofocus inspection: confirmed front focus, so recalibrated the autofocus unit.
Inspected for the resolving-power issue you pointed out, but could find no issue with lens accuracy.
Inspected the operation of all components.

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:

Nikon repair statement for my Nikkor 17-55 f/2.8 zoom, in
Japanese
Report on the autofocus inspection: could find no issue with the focus point. Everything was within specs, but we recalibrated it anyway.
We inspected for your complaint, but could find no flaw at this time.

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.


All 8 comments so far, oldest first...

Congratulations, you must be very relieved.

— comment by nils on January 20th, 2007 at 10:44pm JST (10 years, 9 months ago) comment permalink

Jeffrey,
thanks for your persistence and method in dealing with your camera/lens issues.
I have a d80, a 50 1.8, 18-200 vr and a new 70-200 2.8.
I have found that the 70-200 is not as sharp as it should be.
I have taken test shots with your chart and the 50mm and the 70-200. Both appearr to show backfocus. I would appreciate if you would look at the shots.
Best Regards,
Michael Oard

— comment by Michael Oard on July 16th, 2007 at 4:20am JST (10 years, 3 months ago) comment permalink

Hi Jeffrey, thank you for the excellent article and test chart.
I have the D300 and 18-200 VR lens and have always been a bit disappointed with the crispness of the focus -(i.e. it wasn’t!). This was especially annoying as the 18-200 lens performed really well on my previous D70s.
So, having used the chart and your instructions I have found that the sharpness in the lens achieves acceptable quality using the AF Fine Tune – using a setting of -16!
I am not sure whether that means I should get the camera / lens recalibrated by Nikon? Any thoughts. I do not have any other lenses at the moment. Are there any downsides to just running as it is?
Many thanks again.
Brian

I don’t have a D300, but I think the whole point of the AF fine Tune feature is to use it exactly as you’ve done. If it now focuses well, count your blessings and go take some pictures 🙂 —Jeffrey

— comment by Brian C on May 18th, 2008 at 5:44am JST (9 years, 5 months ago) comment permalink

Thanks for this page. I have a bad front-focus problem on my 17-55 f2.8 DX lens at the 17 mm end. I posted a question on the Nikonians lens forum, and the only reply so far is from a certain “Len Shepherd” who was explaining that I don’t understand how to use AF on my D200 correctly!

I’ve lodged the problem with the Nikon UK website. Hopefully I can get the lens calibrated. I will plan to send them the lens only, since the D200 focuses every other lens I own perfectly.

Don’t worry about the “Len Shepherd” notes. He’s either a robot who blindly responds with “you are stupid! You know nothing!” notes to every post, or a fairly pathetic human who does the same. —Jeffrey

— comment by James Gilbert on September 2nd, 2008 at 1:20am JST (9 years, 2 months ago) comment permalink

Boy, this Len Shepherd guy gets around. I just read this update to your lens focus saga, and I thought his name sounded familiar. Last spring I posted on Nikonians.org about some apparent focus inaccuracy with my 200-400 f/4 lens on my D200, and one poster kept responding with what I felt were unreasonably critical comments. I just checked and sure enough, it was our friend Len.

Anyway, thanks a LOT for your contributions to focus calibration. I’m hoping a future Nikon DSLR will support auto-calibration, where you just point the camera at a test target and it figures out the appropriate AF fine tuning value for you. There’s no reason for this to be a manual process.

— comment by Brett on December 23rd, 2008 at 11:38am JST (8 years, 10 months ago) comment permalink

Hi Jeffrey,

Thank you very much for taking the trouble to pursue this issue to a successful conclusion and particularly for informing others about your experience. Your postings and the responses they have elicited have been both useful and entertaining. I hope others will now be encouraged to perform such testing on their equipment.

By the way, have you ever received an apology–or, at least, an acknowledgement–from the “loudmouth” Len Shepherd? I notice his obnoxious broken record continues to play on the forums.

No, I haven’t, and I wouldn’t expect one, because people who are always right about everything never have a need to apologize, only endure the ignorance and stupidity of others. —Jeffrey

Best regards, Bill

— comment by William Halvorsen on January 1st, 2009 at 12:06am JST (8 years, 10 months ago) comment permalink

Hello,

Thanks for you tutorial. You test chart was very helpful. I was very easy for me to confirm that I have a front focus. The issue is that it’s a lens front focus, not a body front focus. Tested the lens on another body to double check this. Now I just have to find a service that do lens calibration. My camera body, a D80, doesn’t have focus correction.

— comment by Adrian on February 12th, 2012 at 3:42am JST (5 years, 8 months ago) comment permalink

Excellent posts. I thoroughly enjoyed your input. If there’s a question with regard to AF or any equipment in which results aren’t achieved the way it’s intended, it’s usually equipment malfunction, test inaccuracy, or user error (or a combination). To express or insinuate that it must be user error – esp. in a photo site – suggests that the problem is the troll. If someone can’t add to a discussion, that moron is worse than any problem with gear.

— comment by Karl on October 19th, 2012 at 9:21pm JST (5 years ago) comment permalink
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