Nikon 80-200 AFS f2.8D focus issue

[thequintessentialman]

Sort of suspected the focus on my "old reliable" zoom is less than optimal, for a while now. I see photos on the interweb with the same D800 body and newer "VR" versions of this zoom, and the sharpness is much better. At first I thought it was just my skill level (and a large part probably is) but after acquiring a Sigma Sport 150-600, the difference in sharpness was quite noticeable between the two with the Sigma being the sharper. This is even with manual focusing of the Nikon using the LCD viewer zoomed in.

 

Last night, I found a focus calibration scale online, and I set up a test bench; I've NOT touched any calibration controls. The lens is a little front focus at 200 and a little more back focus at 80. I neglected to to measure the lens to subject distance but the shots were taken at about 6'. Just for curiosity, I took a couple of shots with the Siggy too but moved it back a bit. The scale on the calibration tool appears to be in inches after allowing for the angular offset. My best uneducated guess is the lens front focus is about 0.25" at 200mm and about 0.5" back focus at 80mm. There is still noticeable difference in sharpness between the Nikon and Siggy at any distance. The Siggy follows the same front back pattern with slightly front focus at long end and a little back at short end (an almost dead even split).

 

FWIW, this was discussed on another forum but I had not done any testing. My thought is, that even though this lens was initially designed for a Full Frame film camera, the detail afforded by the 36 mpx sensor is is just too much for this older lens. I'm seriously considering the Tamron 70-200 now as a replacement. FWIW, the Nikon has been back a couple of times in the past few years to the Nikon Service Center.

 

Thoughts, concerns, etc...?

[Andrew Garrard]

By all accounts the 80-200 AF-S is a substantial optical improvement over the AF(-D), which definitely had focus accuracy issues and is somewhat limited on sharpness, especially at close range. I'd not be surprised to know it can't keep up with a 70-200 VR2, though, let alone the latest one. The higher resolution sensors do show up lens limitations.

 

I've no personal experience (the only 80-200 AF-S I've touched was broken when I was considering buying it, and I gather parts are limited). But a lot of glass has benefitted from redesigns for new sensors.

 

You might want to stick your Sigma on their dock, which allows you to adjust focus at both ends of the zoom and at different focus differences. I've not had huge luck with my Art lenses even so, but some of that may be user error (although I really don't understand why they made it so you have to put the lens on a dock - if you could plug it in while it was on the camera, life would be much easier).

[thequintessentialman]

That's good to know about the Sigma base. I was aware it could make adjustments but was under the belief it was either one end, the other end, or somewhere in the middle. (A base is on the list though; there have been some updates to the focus speed, which is already pretty good),

 

Regarding your docking question, from my limited PLC background, my thought would be possible interaction of the camera electronics and the "programming module". We are also talking about two different competing vendors one of which doesn't really want to play with the other. Calibrating first off camera, then calibrating the camera to the lens, should increase accuracy. Again, this is from a controls automation perspective and not camera electronics so I could be wandering lost way out in left field...

[Wouter Willemse]

The AF-D 80-200 f/2.8 does often suffer pretty severe focus issues at 200mm at close distances, which may impact the testing for back or front focus. To be on the safe side, I'd do the tests at a slightly shorter focal length (say 180mm) to avoid this issue.

 

[Edit]: sorry, I now see the AFS in the thread title - which lens is it exactly that you have? What I wrote applies to the AF-D lens, not the later AF-S lens.

[thequintessentialman]

AF-S Nikkor 80-200 f2.8D.

 

The issue is not back or front focus so much as just a lack of overall sharpness compared to the newer 150-600 Sigma Sport I have. The question is could I get noticeably better performance (sharpness) from a newer lens? I don't know if it's the age of the technology, the state of this particular copy, or my expectations that's causing the problem. I don't recall ever taking a shot with that Nikkor that did not benefit from a little sharpening PP.

[Andrew Garrard]

> That's good to know about the Sigma base. I was aware it could make adjustments but was under the belief it was either one end, the other end, or somewhere in the middle. (A base is on the list though; there have been some updates to the focus speed, which is already pretty good),

 

Yup, although I've not tried it on a zoom, I believe there are several points in the zoom range and several points of focus distance that you can calibrate. I wish Nikon would have done this with their own AF fine tune.

 

> Regarding your docking question, from my limited PLC background, my thought would be possible interaction of the camera electronics and the "programming module". We are also talking about two different competing vendors one of which doesn't really want to play with the other. Calibrating first off camera, then calibrating the camera to the lens, should increase accuracy. Again, this is from a controls automation perspective and not camera electronics so I could be wandering lost way out in left field...

 

You don't really "calibrate off camera" - the dock is just an electronic connection with no optics. You try the camera focus, see how close it is (either by contrast-detect focus and comparing to the AF confirmation dot or by trying contrast detect and seeing what you get), take the lens off the camera, stick it on the dock, make an adjustment, move it back to the camera, repeat. At least four times for a prime, and many more for a zoom. Getting the camera where it has a convenient focus target at the required distances and shuffling the lens back and forth to a laptop (at least I can clamp the camera to a tripod; for a big zoom, I'd have to take the lens off the tripod, or at least disconnect the camera and reattach the dock with the lens tripod mounted) doesn't make me happy from a "dust in the camera" perspective. If they'd just made it so you plugged a micro-USB cable into a (covered) socket on the lens, then (at most) turned the camera on and off but otherwise didn't have to do anything, that would be much more convenient. But at least they have the facility to tune at more than one point, which Nikon don't appear to have (fingers crossed for future versions of auto-fine-tune).

[thequintessentialman]

Wow, that's a bit underwhelming. I had envisioned something a little more... user friendly; what you described sounds painful.

 

Thank you (I think.)