What are some of your favorite/most used lesser known features of the open source Canon firmware CHDK? Have any helpful scripts you used?
I've only used a few features. I've found the intervalometer and motion sensing scripts useful. I've used the RAW feature, and realized most P&S cameras don't include it because their memory can't handle it (unless you like waiting 10 seconds to take another photo). I also liked the ability to optically zoom while taking video.
IEEE recently released a very interesting article on this very subject, I thought some of you out there might find it interesting, and it does give alot of good ideas as to what you can do with the CHDK. They say, the real power is in writing your own scripts. Apparently it can do motion detection, which will leave to some absolutely stunning pictures. Makes me tempted to get a Canon Powershot, just for that purpose...
Having only tinkered with CHDK a little bit, I imagine other answerers will come up with lots of interesting features to mention. That said, the one that strikes me as a single feature that's likely the most powerful is just the very fact that one can write scripts for it, to do (almost) whatever you might want to do.
Granted, one has to have (or build up) some programming skills to really make use of this, but the fact that it's even an option to write an arbitrary script in BASIC or (more to my tastes) LUA strikes me as huge.
For example, to be able to say "Hmm, someone keeps knocking my trash can over", and writing a script to do motion detection and get a photo of the culprit (dang raccoons*! ;)
Or perhaps you want to do focus bracketing... or some sort of strange time-lapse setup... or... any number of things become possible.
As for particular favorites, well... I'll have to use it more before I have the experience to add anything useful on that front.
Happy shooting! (and scripting!)
* Note: I'm saying this in jest, just for illustrative purposes. I have nothing against raccoons, and my trash can has not been knocked over recently, by any one or any thing. Just pointing out something that could be a "helpful" use of a "lesser known" feature.