Less of our Cine-Mod and more of a custom modification, this particular lens was sent to us by a client looking to use his Summilux-R 35mm on his Canon 5D which called for some minor, but precise modification. Normally, the rear housing of the Summilux-R 35mm protrudes too far when the focus ring is set anywhere near infinity. The protrusion impacts the mirror and prevents the lens from mounting or the shutter from functioning correctly.
In most cases, clearance issues for Leica-R’s stem from a protruding safety tab at the back of the lens. But in the case of this lens, the protrusion is found to be a part of the rear optical group’s housing.
Sitting just above the rear element in this 35mm f/1.4, holding the glass in its place, is a lock ring and its accompanying threads. It's the lock ring and threads that cause the collision with the mirror within 5D’s, and is in need of the modification.
This modification requires disassembly, careful measurement, mounting, and a bit of precision machining. The results are practically unnoticeable when done correctly - but allow the 35mm Summilux-R to work on a wide range of Canon EF mount reflex cameras.