I do not understand or accept the sharpness, nor the vignetting rating for this lens, which I used for years on 1Ds and 1Ds MkII bodies. I had a good sample adjusted for focus errors by Canon, and it was as sharp as the old 24-70mm lens, without the dehumanizing curvature of field of that implement. It was worst at 35mm where at F5.6 the border areas even centre-stage were not exactly unsharp, but distorted slightly. Other than that, it is, or mine was, an excellent machine-much better than the current AFS VR and/or G Nikkor copies.
Its only limit was speed, and the border issue at 35mm and softer sides wide open at 85mm, and a lesser contrast than has the old and excellent 28-70mm f3.5-4.5 II Eos lens, whose resolution and contrast is higher, but only by a little bit.
This lens can certainly manage more than your claimed 6Mp resolution at the longer focal lengths (all that yellow in the "sharpness" page baffles me.
As a newcomer, am I misreading the charts? I was looking at the same sharpness chats for the 17-55mm f2.8 Nikkor, which you appear to be claiming has around 1-5 Megapixel resolution on a Nikon 7100!! Your chart shows a thick yellow band going into the red all around the 17-55mm Nikkor's sharpness at anything anyone buys the lens for, which disturbs me. Do you not manually focus for your tests, and is this focus error? as noone buys them for 1-5MP resolution.
There are dozens of these lenses here now in the UK secondhand, and is this true and why, or are people getting rid of them because they genuinely have almost no resolution at all, at the longer focal lengths?
Will I be returning the one I have on order then. How can it have such a dreadful performance, when surely it should be as good as it gets??