This is a rare lens, usually made for the Exa in Exakta mount with a lightmeter screwed to the top. I found one in M42 mount for the Edixa. I haven’t used it much, but it is definitely an interesting tool for bokeh photography. The look is similar to the famous Meyer Primoplan 58mm f1.9 lens, however it is not quite as extreme, since it has a shorter focal length at the same aperture. That being said, it is very sharp and very contrasty, beating the Primoplan easily in both those categories. This is an excellent lens, and one to look out for.