In article , nms@inamess.vip.best.com says...

>I don't think statement about corner performance is true, at least not for
>my 80-200/2.8D. Here are my observations:
>
>Slight vignetting at f/2.8 (80mm)
>Corners moderately soft at f/2.8, reduced by f/5.6, absent at f/8 (80mm)
>Extremely slight overall loss of sharpness at f/2.8, gone by f/8 (80mm)
>Performance at 105mm similar, but the loss of sharpness at f/2.8 seems
>slightly greater, may be due to greater magnification of the objects I
>fixed upon.
>Performance at 200mm better at f/2.8, with virtually no loss of sharpness
>or vignetting in the corners, but corner peformance remains the same
>throughout the zoom range, ie, never quite as good as the center.
>*Extreme corners worse in one direction than the other.*
>
>I also have the Sigma, and agree that the Nikon is a better lens. The
>Sigma's colors seem more muted and the lens is prone to flare, although
>the sharpness is not wanting. Given the choice I'd take the Nikon in a
>heartbeat.
>
>Nick Silva

Hmmm, where DO you find these defective Nikkors?? ;-) (Your 35-70 f2.8
also showed optical misalignment [all four corners did not have the
same sharpness], so I would not base a judgement of the quality of the
lens type on this defective sample, other than to note that it exists.)
My 80-200 f2.8 AF Nikkor is fine everywhere, center-to-corners, except
near minimum focus near 200mm - which seems to be representative
performance for this lens (and all four corners match in sharpness...;-).
Hope This Helps