Plaubel is probably best known for its Makina line of cameras, but not to be confused with the Japanese lens maker Makinon, although there were some models of Makina cameras made in Japan after the 70s. This Plaubel 13cm f4.2 was used on one of its cameras. I found a picture of the camera it was originally used on, currently selling on eBay. Looks like the lens is quite old, probably from 1920s. I got this lens from the camera show a few months back, from Abraham’s junk bins. Tried it on the Nikon D810, and the result was disappointing, at least at infinity. I could not get a very sharp pictures, either because I didn’t focus properly, or the lens just does not work well with the sensor on the D810. Tried on the Sony A7 and the result was much better.