Pentax 31mm 1.8 Cokin P filter adapter

This adapter mounts to the Pentax 31mm limited 1.8 lens and allows direct mounting of Cokin P filter adapters including this 3D printable version available here: https://www.thingiverse.com/thing:2945377

Due to the inbuilt hood on the 31mm, the use of square filters is difficult. The beauty of this system is that it also leaves the filter threads free to use normal circular filters in combination with square ones.

It’s a two-piece design, with a main ring that slides onto the front of the