Pentacon 2.8/80 Projection lens to Nikon F-mount adapter

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This is a high-quality tube adapter designed specifically to attach to the front of a Nikon camera, allowing you to screw in a Pentacon 80mm f/2.8 projection lens and achieve stunning soap bubble bokeh at a fraction of the cost of a Trioplan lens. Unlike generic Pentacon mounts, this adapter is tailored for one specific slide projector lens - the Pentacon 2.8/80 AV - to Nikon F-mount. It's possible that different sizes of this lens exist, with some versions featuring a barrel diameter slightly over 51mm (just under 2 inches), possibly referred to as a Pentagon XL. This adapter consists of two parts that snap together easily but can be glued if desired for extra security. Inside the adapter lies a toothed mechanism that complements a groove on the projector, enabling smooth focusing by twisting the lens. To enhance dampening and prevent vibration from affecting image quality, you can glue scrap felt into the adapter's lip. For precise infinity focus, it may be necessary to carefully trim off the last 5mm of the lens's plastic casing, allowing the lens to move closer to the camera. However, be cautious not to scratch the back element while cutting, as this can severely compromise image quality. Update: I've revised the design with a new Nikon F-mount stub, which replaces the previous one that lacked essential features and failed to print correctly due to manifold issues. The updated adapter is thicker and boasts tighter tolerances, requiring excess material removal for seamless camera fitment.