This is a conversion of the Carl Zeiss Jena 5cm f/2 Nickel Sonnar lens, originally for the Contax RF system. The lens has been mated to a Nickel-plated Amedeo Adapter, and both lens and adapter ensured to be in perfect calibration with each other.
This lens dates back to 1934, and is uncoated (aka: pre-war uncoated).
The original 5cm f/2 Nickel formula Sonnar renders a bit differently than the later Carl Zeiss Jena 5cm f/2 formula from 1937 onward. The earlier Nickel formula has the following attributes we’ve observed that 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 than the later Jena Sonnar (Nickel feels more vintage, old world).
These are my observations at least, based off going through hundreds of copies of these lenses over the years.
The lens is RF coupled from 0.7m thru Infinity. Both lens and adapter underwent a service.
Both adapter and lens are nickel plated. The lens can uninstall from the adapter and be used on a Contax rangefinder camera without issue also.
The optics are in excellent condition considering age, and are haze and scratch free. The one optical issue the lens does have is some slight separation towards the outer edge of the rear set. This can’t be seen from looking in from the rear, but can be seen if viewed thru the front element at an extreme angle. We’ve checked the cement status during service, and feel its best to leave this set as-is. The separation area is well outside the full frame image circle, and does not show up when optically testing the lens. The lens renders images with lots of contrast and sharpness for its age, and is possibly one of the sharpest nickel sonnar examples we have come across. Do note, there may be some micro marks or tiny dust specks that we can’t fully remove when servicing and converting the lenses.
As is with most Sonnar formulas, the lens has focus shift at mid apertures. This particular lens was calibrated for f/2.0 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 Jena or Opton Sonnars exhibit.
The lens comes with a push on front metal cap, and a rear M cap. This is the Sonnar to get if you enjoy shooting monochrom.