Kern is a famous Swiss producer of optics, kern lenses are known as super sharp lenses with smooth bokeh. For me it can be compared to Leica, Angenieux, Dallmeyer, Cooke, Berthiot or Kinoptik lenses. The Kern macro Yvar 150mm f/3.3 is an excellent lens, incredibly sharp !!! Always in c mount for Bolex H16 cameras. This lens is rare and has a good reputation. To use on aps-c sensors (Sony A7) or 4/3 cameras (Black Magic, GH4, GH5).
This lens is really incredibly sharp and excellent colors rendition !!!