the Fuji S2 Pro camera is not Fuji technology. The S2 Pro is really the Nikon D100 guts. Amazingly, Nikon allowed Fuji to create, what many people consider (including myself), a better camera with the Nikon technology than Nikon did. shrug Dunno about the S3 Pro. If your camra club friends have EOS cameras, then the lenses are all compatiable with the 300D, 10D, 1D, 1D Mark II and 1DS. They all use EF lenses. I had, and use to swear by the Sigma 28-200mm f/3.5-5.6 lens. And then I shot with the Canon 70-200mm f/2.8 L and 28-135mm f/3.5-5.6 IS lenses and I was shocked by the quality difference. The Sigma shots were definetly softer, lower contrast with lower color saturation than the Canons. But then, your mileage may vary. -=>Donald