The early lenses were specially made for the Hansa with a hybrid mount utilizing ideas from both the Leica and Contax 35mm cameras. Later, Canon changed their mount to the "J" mount, which was basically the same as the Leica Thread Mount (or Screw Mount) with a slightly different TPI (threads per inch).
It's from this time period that a lens I recently bought came from. The Nikkor 5cm f/3.5 was one of the very first photographic lenses they ever designed, along with an f/4.5 and f/2 model. This f/3.5 lens is a close replica of the Leitz Elmar 5cm f/3.5 - you can hardly tell them apparent at first glance:
(Note I have edited out my serial # - just a common practice I have adopted).
Both of these lenses are basically Tessar lenses (4 elements). This was the standard lens for the Leica III and similar cameras, so Nikon was in good company. Note that this lens uses the old standard of centimeters rather than millimeters, so yes it is a 50mm lens.
This lens was mostly made for the Canon and similar thread mount cameras, but a few were also made for the early Nikon S-mount system. It was quickly supplanted by f/2 and eventually the f/1.5 and f/1.4 models.
For some reason, my lens is actually in the Canon "J" mount serial # block, but works perfectly on a LTM -> M converter and on my Leica III. According to the serial #, my lens was made in approximately 1945
In use, the Nikkor is actually a bit more ergonomic in my opinion than the Leitz. The aperture control is on the side of the barrel rather than the front, which is easier to access if one is using a push-on filter or a hood. The apertures are also the more standard scale rather than the odd scale of the Leitz. Also of interest is the filter size. This Nikkor appears to have 35.5mm filters. I have some original 35mm-sized filters for the Nikkor 3.5cm f/3.5 lens that can just barely screw into this older lens. The Leitz cap fits on the Nikkor, so it seems as if it will take the same accessories that fit over the barrel (I have a FISON hood on order, so I will test that soon).
Overall, this lens is a very interesting piece of Nikon history. But how does it perform? I searched around and could find no images from this lens. So I will rectify that now. Overall, it performs as one would expect, with lower contrast than modern lenses, a classic look, and pretty smooth out of focus rendering like a Tessar usually has, with poor corner performance unless stopped down pretty far.
That being said, if you have the itch for a traditional Tessar lens for a screw mount camera, the Leitz Elmar is probably a better idea. I was extremely lucky to purchase this lens for less than you can usually find an Elmar for, but, most dealers or eBay sellers are asking a lot more than that. Keep your eyes open though and you might get lucky.
Enough talk, here's some photos. First, here's some images from my Leica M9, processed in b&w:
I also shot a roll of Tri-X in my Leica III. It was a joy to shoot with the original Leica screw mount camera. Here's some of those images:
I'm looking forward now to shooting a bit of color film with this lens. I also might do a direct comparison with the Elmar sometime. I hope you enjoyed seeing this bit of Nikon history.