Normally, when I get a new lens, I try to test it corner to corner by shooting an horizon picture where the horizon is tilted corner to corner. Like this one:
I do that at various apertures so as to see the progression in sharpness. The test also gives information on AF accuracy and vignetting. Basically, it is a deceptively simple yet extremely accurate landscape test. I can also compare different lenses of the same focal between them (e.g. zoom versus prime, at different apertures, etc...).
Today, I tried to compare two different lenses mounted on two different cameras. One is the Hasselblad HC 50mm - II, mounted on the H3DII-50. The other is the Nikon 35mm f/1.4 G, mounted on the D800. The HC 50 - II is an excellent lens, but so is the Nikon (in any case it is the best I have that gives that field of view and mounts on the Nikon). The HC 50 - II is full open at f/3.5 (it does not get much sharper closed down...), the Nikon 35mm is closed at f/4.0 (and it only gets a bit sharper when closed down to f/11, but not that much).
To ease the comparison, I cropped the horizon and rotated the pictures, then put them on top of each other. The D800 picture is scaled up to match the resolution of the Hasselblad. You get this:Clic here
to see the full resolution (on flickr).