Perhaps not exactly on topic, but I just picked up c't Digital Photography #14 and in it they do tests with Canon, Nikon and Sony using APS and 24x36 lenses (normal zooms) to see if the stories about "FF" lenses on APS-C being better than the APS-C lenses. The verdict was, on page 38:
Quote: At the end of the day, there are no real arguments for using full-frame lenses with an APS-C camera.
They tested three lenses with each of three APS-C cameras. Here's the test gear. The only standout among the nine lenses was (surprise, surprise) the Vario-Sonnar, but even then was quite close.
Canon EOS 7D:
- Canon EF-S 17-55mm f/2.8 IS USM
- Canon EF 24-70mm f/4.0L IS USM
- Tokina AT-X 17-35mm f/4 Pro FX
Nikon D7100
- Nikon AF-S DX Zoom Nikkor 17-55mm f/2.8G ED-IF
- Nikon AF-S Nikkor 24-70 f/2.8G ED
- Tamron SP 24-70mm f/2.8 Di VC USD
Sony SLT-A77
- Sony 16-50mm f/2.8 DT SSM
- Sony 24-70mm f/2.8 ZA SSM Vario-Sonnar T*
- Sigma 24-70mm f/2.8 EX DG HSM