Words such as RAW files, bracketing, full manual control, over exposure, zebra mode, live histogram, grids etc are usually limited to DSLR cameras, although Canons powershot cameras come with full manual controls, they fail to provide users with the premium DSLR features. Canon Hack Development Kit (CHDK) is a project started by Andrey Gratchev to help users get the maximum out of their Canon cameras.
How CHDK works?
Every camera has a firmware in it; CHDK adds some more functionality to it. CHDK custom firmware works independently i.e. it will not make changes to your original firmware. The custom firmware has to be stored into the SD card due to which users have the option of starting up the camera with original firmware or CHDK custom firmware. the custom firmware can be deleted at any point of time without making permanent changes to your camera.
CHDK Highlight Features
Professional control - RAW files, bracketing, full manual control over exposure, zebra mode, live istogram, grids, etc.
Motion detection - Trigger exposure in response to motion, fast enough to catch lightning.
USB remote - Simple DIY remote allows you to control your camera remotely.
Scripting - Control CHDK and camera features using ubasic and Lua scripts. Enables time lapse, motion detection, advanced bracketing, and much more.
Disclaimer: Loading CHDK into your camera will void your camera warranty. since CHDK firmware doesnt edit the original firmware there is minimal chance of the camera being damaged.