Compatible with Pentax K Auto Focus Mount (PK AF) Lenses to C-Mount (1″ Screw Mount) Cine & CCTV Cameras with Built-In De-Clicked Aperture Control Dial
Connect your favorite manual Pentax lenses to your Back-Bone modified camera with this C-Mount adapter. Fully automatic lenses can also be connected but please note that there is no electrical connection via C-Mount, so auto-focus will not function. The iris on fully automatic lenses can be controlled using the ring on the adapter. 35mm (full frame) lenses will experience a crop factor of 5.6x on modified GoPro cameras.