There are numerous software packages that will autofocus a telescope by taking photos and judging where the minimum size star disk is. This includes Focus Max as a dedicated focus application, and/or features within telescope and camera control software like APT, NINA etc.
I use Canon DSLR - astro modified 5D Mark IV, and more recently a QHY 128c with Canon mount. I use Canon and other Canon-mount lenses from 14mm to 200mm.
I already found that using a stepper motor with a Cine-style follow-focus gear on the lens can step much more finely than I can by hand. I did this "manually" meaning I am still judging the spot size by eye. But the stepper motor is much better than turning the ring.
But once I am there I thought hey, why not do autofocus with the same software that one uses for telescopes.
I believe the simplest way to do that is to get an ASCOM compatible controller for my stepper, like this https://pegasusastro...tor-controller/ and then use one of the many software approaches.
What is your experience doing this? Is there any software that is particularly good in this case?