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Lens Recalibration

post #1 of 8
6/13/08 at 10:36pm
Thread Starter 
One of my Nikon lenses is suffering from an obvious de-centering effect, and I'm now exploring the possibility of sending it in for service; but I'm not honestly sure how / if they can correct such a prevalent flaw. If cost is put aside (I think the lens is under warranty, but frankly money is a non-issue in this case), would it be worth sending the lens to Nikon for testing? And, more importantly, can they actually do anything?
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post #2 of 8
6/13/08 at 10:52pm
What do you mean by decentering effect? Can you post some example photos? I would send it to Nikon and ask about what they can do.

It doesn't make sense to have a good lens and have it perform badly. I'd send it in if they say they can do someting.
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post #3 of 8
6/14/08 at 12:40am
Thread Starter 
It was my understanding that a "good" lens sample should have each of its elements machined such that the absolute center of the frame yields the highest possible resolution. The less accurate this highpoint, supposedly, the faster the surrounding areas of the image deteriorate in terms of resolution; or something to that extent.

Regardless of whether or not I'm describing the issue correctly, the fact is that the lens obviously has some issue with its build and image quality - as the results at 200mm are unusably soft, and unimpressive even at 80mm. It's getting pretty late and I don't have enough comparison shots to demonstrate the issue, but tomorrow for sure I'll have some crops at different aperture values and focal lengths which show the lens's weakpoints. (The lens is a supposedly pro-grade 80-200 f/2.8, renowned for its sharpness and contrast as many of you are aware).
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post #4 of 8
6/14/08 at 5:03pm
Thread Starter 
Alright guys, here are a few sample shots to show the dramatic drop in quality from 80mm to 200mm at various apertures. I chose a fairly detailed subject, used aperture priority and autofocus, and kept the ISO at 100; while maintaining a steady position using a monopod. I figured that full size samples would best illustrate the problem, so I've linked thumbnail versions of each image which you can click through at full resolution.

80mm @ F/2.8:


80mm @ F/3.5:


80mm @ F/5.6:


200mm @ F/2.8:


200mm @ F/3.5:


200mm @ F/5.6:


Alternate Picture:

80mm @ F/2.8:


200mm @ F/2.8:


Note the hazy, outlining effect that occurs wide open at 200mm - it's a little like ghosting, but occurs regardless of the light source.
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post #5 of 8
6/15/08 at 12:00am
Thanks for the samples. It's really quite soft wide open @ 200. I would say it's near unusable unless you're aiming for that dreamy effect. I think it's just about usable stopped down a lil'. Do things improve further around f/8-11? I have to say my 70-300VR can deliver better results at 200mm/f5.6 (largest aperture at 200 being f5.3). No use being able to shoot at large apertures when the results are lacklustre. Your 80mm samples aren't poor though. I would be very happy with those results.
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post #6 of 8
6/15/08 at 12:55am
Thread Starter 
Quote:
Originally Posted by milkpowder View Post
Thanks for the samples. It's really quite soft wide open @ 200. I would say it's near unusable unless you're aiming for that dreamy effect. I think it's just about usable stopped down a lil'. Do things improve further around f/8-11? I have to say my 70-300VR can deliver better results at 200mm/f5.6 (largest aperture at 200 being f5.3). No use being able to shoot at large apertures when the results are lacklustre. Your 80mm samples aren't poor though. I would be very happy with those results.
Obviously the results return to a usable level around f/6.3 @ 200; but then again, I didn't spend a grand to get "usable" output nearly 4 stops down. I normally wouldn't be so anal with regards to resolution, if it weren't for the lens's reputation as being the sharpest in Nikon's lineup or for its pricetag. Luckily, the 105, 135, 145 and 155 focal lengths follow the sharpness trend of 80mm, but clearly something is amuck with those last 45mm.

Thanks for your input, though; I wanted to make sure my OCD wasn't kicking in as it usually does.
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post #7 of 8
6/15/08 at 8:39pm
Thread Starter 
Alright, now that I've established the definite presence of a problem, the current issue is fixing it. Is there some way to get in contact with Lens Service Centers (if such things exist) to evaluate the costs of a job or whether or not a fix is possible?
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post #8 of 8
6/16/08 at 12:04pm
If you go to the Nikon USA website, you should be able to find an Authorized Repair Station near you, listed under the support section.
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