What? SMC-M and SMC Takumar 50/f1,4 are junk lenses? The Pentaxes 50/f1,4's are among the very best lenses ever made for the 35mm format. Even my Leica friends who are probably more loyal to Leica than to their wives will admit to the greatness of the Pentax 50/f1,4's.
I'm thinking, but mostly day-dreaming, of getting a Jupiter-9 myself. Anybody here ever try the Soviet Helios-40 85/f1,5 monster?
As for Pentaxes, I don't have any off-brand "junk lenses" at the moment unless I count the Soligor 500/f8 mirror lens that I never use. I have a Belorussian 8mm/f3,5 Peleng on the way so I'll wait and see.
Soviet quality control is non-existent so occasionally you'll get a dog. However, I've been lucky to know a few people that are able to turn these dogs into jewels. Most of them were, after all, based on Zeiss designs and used Zeiss tooling confiscated after the war. Early Jupiters even used original Zeiss glass. My favourite "junk lens" is my Jupiter-3 50/f1,5, which is a copy of the great Pre-war Zeiss 50/f1,5 Sonnar made for the Zeiss-Ikon Contax camera. This lens has a very unique signature wide open. It's bokeh goes from a machine-like quality to a buttery smooth Some people like it, some people don't. I love it. It's a rangefinder lens and not a SLR so I'm not sure if it will count. When I got it, it was an absolute dog. Focus was off 30cm at 1m and 1m at 5m. This made the lens unusable with larger apertures than f2.8. The focus ring was also so stiff that turning it would cause the lens to start unscrewing from the mount. After the first test-roll I got cramps in my hands. I sent the lens off to Brian Sweeney, who is a guru at culminating Soviet lenses. When I got it back, it was a night and day difference. This lens is now one of my favourites. Here's some photos taken with it.
Wide-open, hand-held at 1/15th about 2.5-3 metres away.
f2,8, hand-held, about 4-4.5 metres away
f8
Sorry for the non-Pentax content. Please let me know if I was out of line.