Pentax 31mm 1.8 Cokin P filter adapter

thingiverse

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 lens, it’s prevented from sliding too far back by two tabs. A secondary clamping ring then slides into place and helps to prevent the whole thing sliding forward. Simply print one of each part, the main ring must be lined with an adhesive felt tape or similar. I’ve used a Moroday brand adhesive felt tape of 3mm thickness. Supports not required with correct orientation. Designed and printed in ABS, please be aware other materials may affect fit due to shrinkage, or lack of. Best to print the main ring in black to reduce reflections. When mounting, mount this adapter to the Cokin adapter first, then attach the lens, and then clamp in place.