From CHDK website:
The current set of extra capabilities fall into six categories:I am looking forward when a similar project is realized for the Canon DSLRs.
- a. Enhanced ways of recording images - you can capture still pictures in RAW format (as well as JPEG), and for video images you can have increased recording time and length (1 hour or 2 GB), and a greatly increased range of compression options.
- b. Additional data displays on the LCD screen - histogram, battery life indicator, depth of field, and many more.
- c. Additional photographic settings that are not available on the camera by itself - longer exposure times (up to 65 seconds), faster shutter speeds (1/25,000 sec, and faster in some cases), automatic bracketing of exposure, etc.
- d. The ability for the camera to run programs ('scripts', written in a micro-version of the BASIC language) stored on the memory card - these programs allow you to set the camera to perform a sequence of operations under the control of the program. For example, a camera can be programmed to take multiple pictures for focus bracketing, or take a picture when it detects that something in the field of view moves or changes brightness.
- e. The ability to take a picture, or start a program on the memory card, by sending a signal into the USB port - you can use the USB cable to take a picture remotely.
- f. The ability to do a number of other more useful (and fun) things, such as act as a mini file browser for the memory card, let you play games on the LCD screen, etc.



