Debug log attached.
It's the usual focus related crash ( IsFocusLensHandle() fails ), CHDK and the firmware is trying to take control of focus at the same time. I don't think anybody has solved this. As you noticed, disabling Canon AF doesn't help.
The D30 has at least two zoom speeds: Quite fast while idle, very slow during shooting video.
Where would I start to find out whether this can be manipulated via native calls?
You can find lots of named event procedures in the CHDK source:
funcs_by_address.csv (all names ending with _FW are event procedures, remove "_FW" from their name when using them in a script.
Actual
usage is much more complicated though:
- you need to find out how to register them
- you need to determine the number and the meaning of their parameters
- some of them can be dangerous to the hardware
- you can expect lots of crashes (even when using correct parameters)
I was experimenting with some ComputerZoom (short form: CZ) event procedures a while ago: one of them caused the lens to extend in playback mode (!), and all those I tried crashed the camera during video recording.