Tamron - Pentax 15-30mm 2.8 150mm Filter adapter

thingiverse

EDIT 6/618 - Added Filter mount V2 - shaved 2mm off the original mount to bring the filter down closer to the front of the lens and reduce possibility of vignetting. Added Double filter mount - for mounting two filters simultaneously without the need for printing a second squat mount, this also makes it more compact and reduces vignetting. Added Outer ring 10mm inserts - Holes for the threaded inserts are deeper to allow M4x6x10mm brass threaded inserts, making it easier to find a screw of suitable length. 150mm Filter adapters to suit Tamron/Pentax 15-30mm 2.8 lens. There are two adapters available, the basic filter adapter (printed in brown in the photos) is a simple ring that slips over the lens. Rotation is possible but a little stiff. The other (printed in green and black in the photos) is a two-piece design with an inner ring that has four tabs to prevent the adapter from rotating and being pushed too far down. A second outer ring is fixed to the inner ring with two M4 screws, which allows much easier rotation. 4x Brass threaded inserts are inserted into the adapters, filters mounts are then attached and can be stacked for multiple filter use. This system does not vignette with a single filter attached, however stacking filters/some rotation will induce vignetting. Additionally, a magnetic mount system is available here: https://www.thingiverse.com/thing:2945482 Though, this does vignette on the 15-30 at wider settings, depending on your configuration. I’ve lined the inside of the rings (where it contacts the lens) with a 3mm thick adhesive felt tape (Moroday brand used). Designed and printed in ABS, please be aware other materials may affect fit due to shrinkage, or lack of. Best printed in black to reduce reflections. For the Basic adapter you’ll need to: Print 15-30 Basic filter adapter. Line the inside of the ring with adhesive felt tape or product of your choice (rubber and foam adhesive tapes are also an option). Insert 4x brass threaded inserts (M4x6x6mm) into the four holes using a soldering iron, alternatively the holes can be drilled out and the filter mounts can be fastened using washers and nuts. Print 2x 15-30 filter mounts. Print 2x 15-30 Squat filter mounts for each additional filter you wish to mount. Fasten filter mounts to adapter using 4x M4x25mm countersunk screws (longer screws needed for extra mounts). Holes may need to be drilled out with a 4mm drill bit. Optionally, print 15-30 Shroud, and install by sandwiching between the adapter and the filter mounts. For the two-piece adapter you’ll need to: Print 15-30 Inner ring and 15-30 Outer ring. Print the outer ring at high quality/minimum layer thickness, as there’s a small .2mm gap that facilitates installation over the Inner ring. Test the fit of the two rings, secure the Outer ring with 2x M4x~10mm countersunk screws. Sand one/both surfaces until you’re satisfied with the ease of rotation. Consider gluing/bonding the Outer ring as the two 3D printed threads will have limited strength. Follow Basic filter adapter steps above to complete.