If your UAV is big enough to carry a DLSR, here's a great way to control the lens. From Hackaday:
[Vladimir] built an Arduino-based pass-through ring (translated) which intercepts automatic lens controls. It’s meant for use with the Canon EOS lenses which have their own electronics allowing control of things like focus and zoom.
It seems like part of the motivation here was to uses the lenses with other brands of cameras. But [Vladimir] does also talk about the possibility of improving on some of the sensors that don’t perform well in certain climate conditions (think of how crystal oscillators will drift as temperature changes).
The machine translation is a bit rough to follow, but it seems the adapter ring still uses the settings sent in from the camera but has the Arduino clone to translate them into a format that the lens is expecting. In addition to this there is a set of buttons on that small PCB beside the lens which allow for fine tuning the aperture.