A side project I've been neglecting is controlling autofocus on Sony Alpha cameras (specifically the A7ii and A7iii which I have) for the purpose of focus-stacking: shooting a few dozen shots with minimal-step focal differences and blending them all in photoshop later.
It took me a while to find the API; Sony made one then pretty much scrubbed it from the internet and has ignored my emails asking for one :-)
But even with the API, achieving results are tricky. Whether or not the focus motor steps properly seems to be based on how busy the camera is at the time... I'm trying various combinations of [shoot] - [sleep] - [step the focus] - [sleep] - [shoot] but the exactly which of these steps actually succeeds just seems so damn random.
BlackMagic does some pretty innovative stuff. They offered an Arduino add-on board that could communicate with and control their cameras over SDI, including access to the Canon EF mount and its commands.
Somebody did in fact create a control board with a knob to control lens focus through this thing. It can be done. The manufacturers just refuse to do it.
It took me a while to find the API; Sony made one then pretty much scrubbed it from the internet and has ignored my emails asking for one :-)
But even with the API, achieving results are tricky. Whether or not the focus motor steps properly seems to be based on how busy the camera is at the time... I'm trying various combinations of [shoot] - [sleep] - [step the focus] - [sleep] - [shoot] but the exactly which of these steps actually succeeds just seems so damn random.