[Leica] Favorite Non-Leica-Leica Lens?

[photo.forrest at earthlink.net (Philip Forrest)]

Zone focusing with such a lens as a 180mm f/2.8 Nikkor would be next to
impossible without a tripod, measuring tape and an accurately labeled
lens barrel (and some faith!) Novoflex made the adapter without RF
coupling because each focal length would need its own adapter as they
have different rates of focus. I'm currently working on a simple
version of an M42-LTM RF coupled adapter for the Takumar 50mm f/1.4. The
rate of movement of the Takumar is within .20 mm of both of my other
two 50mm lenses for Leica. Adapting a simple push-rod RF cam actuator
inside the adapter is pretty simple. A few hours with a dremel, some
pliers, sore hands, maybe a little JB weld and the adapter would be
done.
Creating such a beast for a very long lens would be more difficult
because of the variable rate of focus. An intermediate cam would be
necessary, but not impossible. Not something for my dremel tool and a
weekend. That's for CAD CAM machinery. If I only had access to a mill
like that, I'd be making adapters for all sorts of lenses.

Phil Forrest