Originally Posted by Ratmagiclady
I've got the 'Takumar' Bayonet 135 2.5, which is sometimes findable even cheaper, but due to less-sophisticated coatings, is probably a lot less consistent. Fun, though, and that's really why I grabbed one:entertainment value and potential quirkiness. They can come cheap (There are SMC versions that are more expensive, generally.)
I just auctioned mine. Needed the money and I practically never used the thing. I started it out at about $30, which is what I paid for it. You could have knocked me over with a feather when it fetched $75! Probably helped that I sold it in Japan and, as best I can tell, the lens was never sold here in the home market. They're very rare here.