A very underestimated zoom lens.
Found pictures taken with these lens that will amaze you,
http://forum.mflenses.com/more-san-francisco-shots-this-time-with-osawa-mc-80-205mm-t31961.html also look @ https://www.flickr.com/search/?text=80%2F205mm
I used it on a Pentax digital camera ( K20 & K5 ) and on a Samsung NX 3000 with Kiwi adapter.
Actualy, on the Samsung the lens was easier to focus manualy, using the image magnification feature.
Anyway, buying this lens is a good deal, even if you would pay up to € 50, compare what you would pay buying a cheap dedicated lens ( a Samsung NX 50/200mm costs approximately € 280 ) and this one wouldn’t be that sharp at the edges.
Lens adapters are nowadays also cheap to find – browse the internet for one – and if you finally have one, a whole new world of reasonably cheap manual focus lenses opens.
This lens is for sale @ http://www.2dehands.be/foto-camera/lenzen/zoomlens/zoom-lens-80-205-mm-f4-5-32-243210000.html