every on has his or her idea of the most influntial Leica camera other than the UR. Many choose the M3 many the M2 and so one. my choice is the model three.
the model lll camera introduced introduced in 1933 gives us to a slow speed shutter speed dial and some refinements like the now ubiquitous strap lugs . But the most important introduction was the new 1.5 times range finder magnification and the needed focusing lever for the new range finder. This was now Leitz full commitment to interchangeable lenses and coincided closely with the introduction of the then new 135mm Hektor lens. The engineers did not feel the previous 1.0 mag range finder was accurate enough to focus this lens at its maximum aperture.
just as a matter of comparison the M3 has and effective range finder base (the distence between the two windows times the finder magnification.) of 62.33 mm, the screw mount cameras with the 1.5 finders a factor of 58.5mm, and the .72 finder by far the most popular M finder before digital is only 49.32 mm, and for the digital M cameras at .68 magnification the effective base drops to 46.58mm. What this all means is that if you could mount your noctilux on a screw mt camera with the 1.5 magnification finder you could focus it more accurately then with any m beyond the M3 even better than the short lived .85 finder, that is if you could see past the lens through the range finder
John aka bosjohn21