Maureen M , Aug 20, 2003; 06:45 p.m.
I'm not sure a simple multimeter would be useful in measuring/analyzing the signals between the camera and lens. Perhaps an oscilloscope would, but even then I would never just start poking around the electronic contacts on a good camera. If reverse engineering were that simple, Sigma probably wouldn't have any compatibilty issues with the EOS lineup.
Why not just use a manual focus lens?