(Click to enlarge)
Closeup of stepper motor/lens ring. I got 5 of the stepper motor/control boards for $12! Lens ring with small spur gear was around $20. Canon 100mm f/2.8 Macro mounted with an Astronomik filter drawer and an ASI1600MM-Cool. 3d printed EOS bayonet mount. BYJ48 Stepper Motor for focus control using a lens ring off of ebay. Mounted tandem with a DIY finder guider using an Orion SSAG.