Leica lenses can be used on Canon EOS bodies (film and digital) with an adapter. However, you lose the transmission of aperture and focus data between the lens and the camera body. This means you have to manually open/close the diaphragm for focusing, exposure measurement is only at working (stopped down) aperture and you do not have auto-flash. It is not a very comfortable solution, but of course costs much less. Btw, the Leica digital back can be used also with the R8, and you can get a second hand R8 body for much less than the R9. I have both an R8 and an R9 and for my needs the differences are negligible. Early R8 are not so reliable, I have heard, but the late ones are.