Pentax 31mm 1.8 Cokin P filter adapter

thingiverse

This adapter seamlessly integrates with the Pentax 31mm limited 1.8 lens, enabling direct mounting of Cokin P filter adapters, including a readily available 3D printable version accessible here: https://www.thingiverse.com/thing:2945377. Due to the built-in hood on the 31mm lens, utilizing square filters proves challenging. However, this system effectively frees up the filter threads for combining normal circular filters with square ones in an efficient manner. This adapter boasts a two-piece design, consisting of a main ring that easily slides onto the front of the lens and is prevented from sliding too far back by strategically positioned tabs. A secondary clamping ring then securely locks into place, preventing the entire assembly from sliding forward. To assemble this adapter, simply print both components; it's essential to line the main ring with adhesive felt tape or a similar material for optimal performance. I've successfully used Moroday brand adhesive felt tape measuring 3mm in thickness. No supports are required when printing correctly oriented. Designed and printed using ABS materials, please note that other materials may impact fit due to shrinkage or lack thereof. For optimal results, it's recommended to print the main ring in black to minimize reflections. When mounting the adapter, first attach it to the Cokin adapter, then secure the lens, and finally clamp everything into place.