The open source project CHDK has built firmware enhancements for many of Canon’s compact cameras. Some features:

- RAW support
- Extra fast/slow shutter speeds
- In-camera scripting language
- DOF calculator
- AutoISO based on focal length
- Exposure bracketing
- Live histogram
- Highlight clipping indicators
- Detailed battery level indicator
- Teathered shooting
- Loads from SD card on power-up (no permanent changes to firmware)

Some first impressions… The UI is organized but far from user friendly. Lightroom cannot open the RAW files. At high shutter speeds the flash power was too high and there was no flash compensation. I ended up holding a white envelope in front of the flash. I tried taking some high speed photos with the new firmware on my Canon SD500. The best photo was taken with the stock firmware. The high speed shutter wasn’t needed for this shot – the focus and timing were more important. These photos were taken in daylight with no additional lighting beyond the flash.

Canon SD500 with CHDK (1/4000s)

Canon SD500 (1/60s)

Nikon D40 (1/500s)

I think I will keep it on my camera for the extra information on the display and the scripting. A few links: installing, download, usage, more usage info