Pixco P/K 16mm C Mount Lens Adapter Ring Suit For Pentax K Mount Lens to 16mm C mount Film Camera ring lens mount adapter|ring lens|lens adapter ringadapter ring - AliExpress
Lens MC Zenitar-K f/2.8/16mm Fish Eye. Pentax mount. Brand New
Pentax 16mm f1.4 C-mount lens review for the Q (and Micro Four Thirds): Pentax Compact Camera Talk Forum: Digital Photography Review