Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:1672146.
An adaptor tube to fit an old binocular objective I had lying around to a Replay XD 1080 camera for high zoom levels. The lens holder had a M40x1.5mm thread which screws into the matching end and the XD1080 is a snug fit in the opposite end. The original camera lens is removed by moderate heating (to soften glue) and unscrewing after the protective bezel is unscrewed. The flat polycarboante window and bezel is then replaced to protect the sensor inside.
The outer diameter has been chosen as 35mm as it is a common scope size and various mounting options are available.
Chromatic aberration is a big problem for single lens, high magnification systems. It can be processed in software to some degree, but a monochromatic filter might be the easiest solution.
Not really satisfied with the image quality, too much light leakage and my magnification is probably too high to get a good image. I was using white filament, painted black. Now I have some black filament I might have another go. Just publishing this model as an example for now.