p.1 #2 · Whats the situation using M series leica ..
It isn't possible to use M lenses on any SLR unless you are happy with only extreme macro capabilities. The register distance is far too large (over 16mm) The only DSLRs that can (kinda) use M lenses are the new micro 4/3 cameras.
p.1 #4 · Whats the situation using M series leica ..
Some of the older M lenses (65mm and longer) can be unscrewed from their RF focussing mounts and fitted with a focussing helix meant for the Visoflex. These lenses can be used on many SLR cameras.