I have been thinking about adding a cheap, old 300 or 400 mm lens to my small collection. There seems to be lots of those lenses availlable, especially for m42 mount. It would be nice to hear your recommendations & to see some photos also, taken with these lenses. I'm also interested in how close you can focus with these, without any extension rings. I know that these old lenses may have lots of chromatic aberrations etc, but it's not so big deal for me.