This is becoming very interesting, are there any sites which show the quality and performance of all these lenses?
There are tons of lens test sites. Some better than others
One thing that most folks rarely understand is what 'sharpness' is actually about. And it is
not just resolution/pixels. Sharpness is a combination of resolution (the fineness of detail) and contrast (how clearly those details are shown). Fundamental to this is the inescapable fact of physics that as resolution goes up, so lens contrast goes down.
If you look at a lens test chart with black and white lines, as the lines get smaller and closer together, the lens renders them as increasingly lighter shades of grey and there comes a point when you can't clearly distinguish them.
In our perception of sharpness, it's this contrast that is more significant. This is what makes an image 'pop' with crisp detail and bright, clean colours. The way this is measured is by Modulation Transfer Function (MTF) and this is the key tool used by lens designers.
Here's a good example of the relationship between contrast and resolution from Leica, their 50mm f/2 in this case
http://uk.leica-camera.com/photography/m_system/lenses/8884.html Click on the technical data on the right, then scroll down to three MTF graphs.
Percentage contrast is on the vertical axis, and the graph shows how this changes across the image with four pairs of lines, at resolution figures of 5 lines-per-mm, 10 lpmm, 20 lpmm and 40 lpmm. Critically, note how as resolution increases, so the pairs of lines drop further down the graph.
Now do a quick calculation of how many lpmm you are asking the lens to resolve with the D800's 36mp sensor, and ask yourself where that pair of lines would be at that extremey high level. Way down near the bottom is the answer, and this lens is one of the sharpest you'll find*.
This is why larger formats always look sharper, in theory. Because the image has to be enlarged less for a given size output and resolution level, the lens doesn't have to work so hard, contrast goes up, and the perception of sharpness is greater.
Good examples of this that nobody would really argue with is say, Nikon D300 vs D700, or Canon 7D vs 5D2. In both cases, the pixel count is very similar and the sensors are of roughly the same generation, but put the same lens on each camera and the full frame cameras always win easily. That's not resolution or pixels, because they're the same, it's lens MFT at work. Plus you get less noise and more dynamic range with the larger sensor (because the larger area simply collects more photons/light) but that's another question.
*Check the MTF graphs for Canon's long L primes, like 300/400/500/600mm, if you want to be truly astonished at how good a lens can get! This is the reason why birders can crop the heck out of cameras like the 7D, because they're using such high quality lenses and image contrast is still quite high even at max resolution. Here's the Canon 500L Mk2, and note that with a theoretically perfect lens all the MFT traces should run along the top. This is as close as I've ever seen, though bear in mind Canon's graphs are only at 10 lpmm and 30 lpmm
http://www.usa.canon.com/cusa/consumer/products/cameras/ef_lens_lineup/ef_500mm_f_4l_is_ii_usm
