Mechanics: This is a Carl Zeiss Jena 5cm f/1.5 Nickel Sonnar from 1933-34. It has a very rare single coating. The lens has been converted to Leica M usage with full RF coupling using an Omnar.
The lens was fully dismantled, with the mechanical parts receiving an ultrasonic cleaning. Lens was then modified to be fused with the Omnar device. Various custom parts and modifications took place. The finish is a combination of existing Nickel Plating and Gloss Black Lacquer over brass. The new mechanics have been pre-brassed to match the brassing of the existing mechanics. Lens is able to focus from Infinity to 0.67m with full RF coupling. The focus ring has metric distance increments and brass finger tab. All new mechanical parts were finished by Camerakote of Staffordshire, England.
Optics: Lens has underwent an optical recentering and compression, to change it’s effective focal length from 52.4mm to 51.6mm, thus permitting the usage of a linear RF cam system in sync with the sub optical block. The lens had an optical cleaning also. There are some minor coating/ micro pitting to the front of the lens, with a tiny scratch to one side on the front element. These don’t seem to affect the image quality at all. Optically, the lens is in much better condition than many of it’s peers from the 1930’s era.
This Nickel Era Sonnar formula is different than the later Carl Zeiss Jena Sonnar formulas from 1937 onward. This formula has what can only be described as even smoother bokeh than the later versions, with a higher field curvature.
It’s a bespoke, one-off conversion. A beautiful vintage Sonnar lens, an all-brass body, fully serviced and ready for Leica rangefinder usage.
Lens comes with a push-on metal cap and rear M cap.