A classic German Democratic Republic lens which gives a lot of the high end Japanese lenses a run for their money. It's a Pentacon 135mm f/2.8 lens with a 15 blade aperture for nice bokeh effects. The focusing is ultra smooth and solid unlike modern plasticky lenses. You could use this m42 on a modern digital camera to get really interesting shots. Also idea for video modes as the focusing is much more precise and noise free. Aperture ranges from 2.8 to f/32 unlike most lenses where f/22 is the top end. Aperture is infinitely variable too so you are not stuck with fixed apertures. you could have f2.9 if you wanted!
Optically milky around edges of glass, centre is clear , controls are smooth - overall a decent example