Tamron - Pentax Adaptable 150mm Filter Holder

thingiverse

My ultimate 150mm filter adapter solution is finally here. Unlike my previous designs, which were optimized for size and ease of printing, this behemoth was designed with no compromises in mind. It's massive, pushing the limits of what can be printed on my machine, and it's highly customizable. The M2.5 fittings allow for attachments of various accessories, currently limited to shade hoods and an attachment loop, but easily modifiable to accommodate different lenses. This adapter fits snugly, rotates 360 degrees with ease, and mounts two 150mm filters without any vignetting (minor vignetting may occur at the widest setting, closest focus distance, and ~45-degree rotation of the mount). Mounts are available for the Tamron/Pentax 15-30mm f2.8 and the Pentax DA 25mm f4 645, but not compatible with the Pentax DFA 25mm f4. A step file is included for the Lens Mount, allowing you to modify it to suit your specific lens needs by adjusting the internal dimensions. To assemble this adapter, you'll need to print: 1x Main Shroud 1x Lens Mount (specifically designed for each lens - currently two available, easily modifiable for most other lenses) 1x Lens Mount Retaining Ring 2x Double Filter Mounts Optional components include: 2 x Sliding Petal 2x Sliding Petal Mount 1x Hinged Petal 1X Hinged Petal Mount 1x Loop Attachment Note that the loop attachment can be substituted for another hinged petal and mount, but combinations of petals different from the one shown in the images may cause interactions and be incompatible. I printed most components using ASA, as ABS is unlikely to be suitable for the larger parts due to warpage. The design incorporates 24x M2.5x3.8x4mm brass threaded inserts, which were inserted using a soldering iron. Eight of these are necessary for the retaining ring, while the rest pertain to the petals (hood) and are optional. These are matched to M2.5x5mm countersunk screws. Each Filter Mount is fixed with 2x M4x~18mm countersunk screws to M4x6x10mm brass threaded inserts, also inserted using a soldering iron. Hinged petals are fixed with 2x 1.6x32mm R clips. Three millimeter thick adhesive felt tape (Moroday brand used) is applied to the inside of the Lens Mount for smooth rotation and secure mounting. To assemble the adapter, simply slide the Lens Mount into the front of the Main Shroud, lightly sand both surfaces if necessary, then fix the lens retaining ring to the Lens Mount.