Visoflex LTM and M bayonet registry difference

[gogopix]

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I have a question. I have an adapter for visofel screw lenses to a MF camrera. I tried the 200mm f4 and it works GREAT. The vendor does not, however sell a visoflex M bayonet for the same camera.

 

Why? the registry difference L39 to M is only 1mm (the M being shorter I think.

 

HOWEVER, I tried to do an optical bench measure of the focus of a 400mm M bayonet Visoflex lens with this camera. The lens flange needs to be 3-6 mm INSIDE the screw flange position! for it to focus. I guess that is why there are not M to MF adapters

 

Also, the 200 and 280 lenses LTM have image circles that cover 6x7 easily there was a LTM to pentax 645 adapter and also some lenses of leica. Seems the longer newer lenses have much smaller image circles. Hewnce they vignette outside a 40mm circle!

 

Is anyone familiar with this? Why was it done? it means that the Visoflex I and the II - III have different thicknesses (to make lens work right. and that is much more than the 1mm LTM to M difference.

 

Does anyone know the flange to film distance for Viso M bayonet lenses?

 

Any info greatly appreciated!

 

regards

[luigi bertolotti]

Visoflex I is quite different in measure (longer) from Visoflex II/III : in fact, to mount a lens with the LTM for Viso I (say, the 200 You have) on the Viso II/III, you must add a significant extension adapter (the OUBIO, well known to Leicaphiles) : I never measured mine but I would say it hase a flange-to-flange distance of at least 5 mm or some more.

I also think that the "long" Telyts 400/560 do not cover MF, on the contrary, I seem to remember that James Lager reports in its book that the Hektor 125 mm (fine lens !) can be used onto a 6x6.