I don't know if this is the first model, but I think that it was. It's the small version of the Carl Zeiss Jena f/2.0 58mm Biotar, and it has no aperture pin. Like a rangefinder lens, when you rotate the aperture ring, the blades close.
This is another camera thing that I've owned for well over a decade. It took me about two hours to disassemble, clean relubricate, reassemble and recollimate. Like many of the East German lens, the barrel and outer components are made from a light alloy, which is prone to scratching, staining and pitting, and no amount of Flitz will fix that. The photos above show it
after I cleaned the lens.
Before I cleaned the lens, I could barely turn both the aperture and focusing rings. Both rotate smoothly now. There are no "click stops" for the aperture, which took quite a while for German camera makers to add.
For size comparison, here it is next to a 50mm AI Nikkor.
I used an M42=>Sony E-mount adapter and put it on a Sony NEX-7. I took it outside and snapped a couple of quick photos to get a feel for its performance. Not surprisingly, contrast is much lower than a modern-day lens, and I would include almost anything after 1960 as a modern-day lens. These early lenses were single coated, and it shows.
It's sharp wide open, although the depth of field is narrow wide open, so be sure to not sway to and fro when you're shooting with this lens.
I'd like to take it up to New York City for an afternoon. Maybe when things and people calm down, I'll do just that. The photos of the rock and tree trunk in the sun were shot at f/8.0. The close focus distance for this lens is about 1 meter (3 feet).
