I read that the Canon EOS (& all digis) registration (which relates to the distance between the rear element and the focal plane or CMOS, doesn't it?) is 44mm and the Nikon and Leica R, 46.5mm and 47mm respectively. Does that mean that Nikon and Leica R lenses can be used - at least, manually - on my 20D? And if so, are there ready-made adaptors available?
Thanks, Dan