Fun with Leicas (the kind that drives you nuts)

[David H. Bebbington]

I recently had the bright thought of using Leica R lenses on Leica M and screw-thread bodies. I therefore bought 2 Novoflex adapters. One is called LEM/LER (Leica R lens to Leica M body). It is approx. 19 mm thick. I have tried it by putting a piece of ground glass across the film gate of a Voigtlander Bessa T (film gate more accessible than Leica M2). It seems to work. So far so good.

I then bought a Novoflex LEI-F adapter (supposed to be Leica R lens to Leica screw-thread body). This is approx. 10 mm thick. I tried this on a Bessa L. The image is out of focus. Not so good.

I find here
http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html
that Leica R register is 47 mm, Leica screw 28.8, Leica M 27.95, so the screw adapter should surely be 18.2 mm thick. Before I return the screw thread adapter, I just wanted to ask if people think that this has simply been assembled wrongly in error or if it actually does something - I can't think what!

Regards,

David

 

[Lee L]

I haven't used the Novoflex adapters, so I can't advise on the problem other than to say your surmises appear to be correct on the screw mount adapter. As you likely know, there's a 1mm greater film-to-flange distance designed into the M mount to allow screw mount LTM adapters to function, so the R lens to LTM adapter should be 1mm larger than the R lens to M mount adapter.

Steve Gandy at cameraquest.com used to sell an R lens to M body adapter that had a "focusing" ring/scale to drive the RF mechanism in the M body. You could "focus" the ring, take your distance reading from that adapter scale, and translate the reading to the R lens. However these are no longer available new, and I suspect rare used.

Lee

 

[David H. Bebbington]

I haven't used the Novoflex adapters, so I can't advise on the problem other than to say your surmises appear to be correct on the screw mount adapter. As you likely know, there's a 1mm greater film-to-flange distance designed into the M mount to allow screw mount LTM adapters to function, so the R lens to LTM adapter should be 1mm larger than the R lens to M mount adapter.

Steve Gandy at cameraquest.com used to sell an R lens to M body adapter that had a "focusing" ring/scale to drive the RF mechanism in the M body. You could "focus" the ring, take your distance reading from that adapter scale, and translate the reading to the R lens. However these are no longer available new, and I suspect rare used.

Lee

Thanks for your reponse Lee. Just for the record, the relative thicknesses are the other way round - if you think about it, an R lens to LTM adapter plus an LTM to M-mount adapter should together be the same as an R lens to M mount adapter, so the R lens to M mount adapter on its own should be fractionally bigger. Anyhow, it's back to the drawing board with the LTM adapter - I shall be interested to hear what the factory have to say.

Regards,

David

 

[Lee L]

Thanks for your reponse Lee. Just for the record, the relative thicknesses are the other way round - if you think about it, an R lens to LTM adapter plus an LTM to M-mount adapter should together be the same as an R lens to M mount adapter, so the R lens to M mount adapter on its own should be fractionally bigger. Anyhow, it's back to the drawing board with the LTM adapter - I shall be interested to hear what the factory have to say.

Regards,

David

David,

Of course you're right, the M body is thinner to accomodate the adapter + LTM lens, so the R to M mount adapter needs to be 1mm longer than the R to LTM adapter. I was in too big a hurry when I posted earlier today, preoccupied with getting errands done and picking up my son from school.

I posted mainly to make you aware of the adapter with the rangefinder drive mechanism. Good luck finding what you're looking for.

Lee