This is a conversion of the Carl Zeiss Jena 5cm f/1.5 Nickel Sonnar lens, originally for the Contax RF system. This lens dates back to 1934, and has had T coating (blue/ orange and purple) applied to the elements. We’ve spoken to Brian Sweeney and others about this particular lens in the past, and it’s one of the earliest T coated Sonnars that exist. The fact that it’s in the Nickel plated housing using the V1 Sonnar formula (Nickel variant, the later Chrome plates Sonnars were recompilations / newer Sonnar formula designs), make this lens even more unique. The original 5cm f/1.5 Nickel formula Sonnar renders a bit differently than the later Carl Zeiss Jena 5cm f/1.5 formula from 1937 onward. The earlier Nickel formula has the following attributes that we’ve observed differ from the later chrome formula:
- Higher Field Curvature
- Smoother Bokeh
- Sharper at central image/ Softer at corner of image (compared to Chrome Jena or Opton)
- Greater Focus Shift when stopping down
- A different rendering the later Jena Sonnar (Nickel feels more vintage, old world).
These are my observations at least, based on going through hundreds of copies of these lenses over the years.
Lens has been expertly converted using an all brass helicoid Omnar lens body, which is custom made for these Sonnar lenses. The lens is RF coupled from 0.65m thru Infinity.
The finish on this lens is gloss black lacquer with heavy brassing, this was to keep in line with the vintage Nickel/ Gloss Black finish the lens came with. The lens has our medium focus feel (most similar to the non-asph Summicron lenses) and is a pleasure to use on both film and digital rangefinder cameras.
The optics are in very good condition considering the age, and are haze free. There is some micro-pitting marks on the very front of the lens element, they are rather hard to see, but there is a photograph in the gallery with a green circle showing where they are. These don’t seem to show up when optically testing the lens, and the lens renders images with lots of contrast. Note, as in most of our conversions, the optics are being reused and repurposed from their original housings into our new mechanical bodies. We strive to get the best optical specimens of each lens in for these type of conversions. Still, due to the fact that these lenses date back to the 1930’s, there may be some micro marks or tiny dust specks that we can’t fully remove when servicing and converting the lenses.
As with most Sonnar formulas, the lens has focus shift at the mid apertures. This particular lens was calibrated for f/1.5 usage. Because this is the Nickel formula version of the Sonnar lens, the focus shift at f/4-5/6 is even greater than the late model Jenas or Opton Sonnars exhibit.
The lens comes with a push on front metal cap, and a rear M cap.