Yeah, I bought one of the el cheapo adapters from eBay. I didn't realize the infinity focus problem before I bought it (undisclosed by the seller
). I guess the silver lining is that it makes me get closer to my subject!
Now I've gone and spent WAY too much for an authentic Pentax one, but I may well still use the cheapo sometimes, because it allows me to change out m42 and K mount lenses a lot faster than the "real" version. I'll probably just keep it attached to my Super-Takumar 50/1.4, which is an awesome portrait lens on a DSLR. I hardly have use for infinity focus in portraiture anyway.