chotaURL

What is CHDK? In short, it adds features you never imagined possible on inexpensive Canon point and shoot cameras. I currently use it on my Canon A590 IS for auto-bracketing, RAW and extremely fast shutter speed. From my experience so far, it is safe and can be loaded on demand—only when necessary. When it isn't loaded, the camera continues to behave as it used to before the installation.

How is this installed? Here's how I got CHDK working on my camera:
1) Read chdk.wikia.com/wiki/FAQ
2) downloaded software from: mighty-hoernsche.de
For my Canon A590 IS, I downloaded: a590-101b-0.9.7-719-full.zip
3) Unizipped the file downloaded in step 2).
4) Copied the unizpped files on to the SD card directions in readme.txt (part of unzipped files)
5) Loaded the files into camera and started camera as described in the aforementioned readme.txt
6) Used the menu options as described here: chdk.wikia.com/wiki/CHDK_firmware_usage/AllBest

The RAW files are not real CRW (Canon RAW files) files. I use dng4ps2 to convert CHDK CRW/RAW files to Adobe DNG format. Downloaded latest version and sources of this software from dng4ps2.chat.ru. This software is available for download at code.google.com/p/dng4ps2/downloads/list?can=2&q=Windows as well. Once I have files converted to DNG format, to process them further and/or to save it in JPEG format, I use Photoshop Elements 7. Photshop and many other software recognize DNG format.