Conon lenses vs Leica lenses

I am a little bit confused.

Its clear that canon lenses for 35mm sensors need to be pretty big due to the bigger image circle.

However i was wondering, why does leica produce lenses which are fairly smaller than any of the canon and nikon lenses? I mean the leica m9 has also a Fullframe sensor.

How is that possible? Or do i judge false and the lenses for the m9 arent that small as i think?

Range finder and SLR are different designs.

My friends Leica 50mm 0.95 (Noctilux) is actually quite large and heavy for a rangefinder lens.

here it is attached to the new Leica M (240):

You are comparing lenses for SLR (Canon /Nikon)and rangefinder (Leica) cameras which are totally different in construction.

SLR/DSLR's bodies have a mirror assembly which is between the lens and the film/sensor but rangefinder bodies do not.

This means that a rangefinder lens is nearer the film/sensor (Leica screw has 28.8mm register, Leica M bayonet is 27.95mm) and can be made smaller and more compact. Canon lens register is 44.0mm to allow room for the mirror.
You cannot fit a Leica lens directly to a Canon or Nikon DSLR body and still have the lens focus to Infinity.

PaulB wrote in post #16127431
You are comparing lenses for SLR (Canon /Nikon)and rangefinder (Leica) cameras which are totally different in construction.

SLR/DSLR's bodies have a mirror assembly which is between the lens and the film/sensor but rangefinder bodies do not.

This means that a rangefinder lens is nearer the film/sensor (Leica screw has 28.8mm register, Leica M bayonet is 27.95mm) and can be made smaller and more compact. Canon lens register is 44.0mm to allow room for the mirror.
You cannot fit a Leica lens directly to a Canon or Nikon DSLR body and still have the lens focus to Infinity.

This is very interesting. It all is a matter of distance between first lens element and sensor plane. It makes a huge difference if you look at the noctilux 0.95 and the 50mm 1.2...

I really believe that someday the compact mirrorless cameras are gonna overcome the big and bulky SLR's...

davidfarina wrote in post #16127439
I really believe that someday the compact mirrorless cameras are gonna overcome the big and bulky SLR's...

Many (if not most) people believe that's true eventually but for many situations you're gonna still have those big bulky telephoto lens

For focal lengths shorter than the register distance, the lens requires a "retrofocus" design, which is why most of the wide angle lenses in use on DSLR's are bigger than the equivalent focal length lenses on rangefinders. The need to add the motor and other components for both the auto focus and electronic aperture are also more bulky again adding size and weight to the lens. Once you move much past the register distance though you start to have to use a telephoto design, which again adds complexity to the lens. For long fast lenses such as say a 300mm f2.8 the difference in size would actually be minimal, as the size of the lens will be limited as much by the size of the glass elements by the other factors. It is interesting to note that there are very few lenses above 135mm focal length avilable of rangefinder cameras.

Alan