re: lens performance comparison
Imaging-resource have their COMPAROMETER to compare pairs of cameras. With lenses, it is not as straightforward; quote from their recent newsletter (abridged):
"Most of our lab images are already shot with a very sharp prime lens: the Sigma 70mm f/2.8 EX DG Macro, one of the sharpest lenses we've ever tested. In fact, we use the same lens (in different mounts) for our Canon, Nikon, Pentax and Sony SLR/CSC lab shots with, so they are directly comparable. Images shown on the Optics page and in the Gallery are shot with the kit lens.
We use a set of "hero" lenses for most of our test shooting: We want to make sure we're testing the camera, not the questionable-quality kit lens it's bundled with. The one missing element in the process is that we don't currently have any workable way of labeling all the test shots so you can see just what lens was used for which one.
We perhaps could add some more characters to the filenames as we're saving them (for instance, Sig70f28, Nik35f2, etc), but some of the filenames are already so long that they cause problems in layouts by pushing table cells wider. We might be able to build something automated, based around the EXIF Reader code we use to extract shutter speed, aperture, ISO, etc, but some third-party lenses masquerade as a company-branded one, so the cameras will recognize them."
This is probably the best one could come up with.