The diminutive Pentax Q takes outstanding pictures - my "Where's Waldo?" post was captured with it. However, I also wanted to utilize it as a platform for lenses which otherwise mount to mirrorless cameras. That is does less well. The Schneider-Kreuznach was sold as an M39 mount. Alas, its closer to a C-mount, but with much tighter threads, and I cannot find a PQ-mount helicoid - at all.
The others are adequate, but with the Pextax Q's insane 5.6x crop factor, it changes things up a bit. For example, it turns the Industar-50 (with the Leica cap) into a 280mm prime, but the 12mm Compar f/1.2 (bottom right) into a 67mm lens. Running middle of the road is the 35mm Fujian (pink) which delivered beautifully rendered pictures on the Sony NEX-3n, but very soft pictures on the Pentax Q. When I take it on my next trip, I'll stick to the two Pextax lenses, and leave the others at home.