Your point-and-shoot camera may not have come with many high-end features, but a simple software hack adds new tricks to dozens of Canon cameras. Beginners will likely be satisfied by their camera's default features, but as your photo skills grow, this relatively easy hack will let you wring extra value from your hardware with no added investment. With it, you can activate an always-on battery meter, shoot high-quality RAW files, read a live histogram to help with exposure, snap much longer--or shorter--exposure times, and more.
The Canon Hacker's Development Kit (CHDK) is an open-source software framework that some motivated hackers have used to add cool features to Canon cameras. Though results vary slightly depending on which Canon digital camera you own, similar sensors and internal parts allow the hack to work with a wide variety of Canons. (Unfortunately, cameras from other vendors are not compatible, and there are some Canon models that don't support this hack.) Since your results might vary, and since Canon might not support its warranty after you use this update, I recommend it only to people who are trying to teach their old cameras new tricks.
From a technical perspective, it's hard to imagine how Canon could ever find out that you tried this hack (and therefore void your warranty), since it does nothing to affect your camera permanently or to alter its firmware; the software runs on your flash memory card, and the camera will return to its default state if you remove the card.
Here's how to download and use the free CHDK software to supercharge your camera.
Get and Install CHDK
CHDK works on dozens of Canon cameras, including the SD870IS, the A570IS, the G7, and the TX1; to see whether yours is supported, check the list at the CHDK Web site. Once you've verified that the hardware is compatible, you'll need to identify the specific CHDK version that you need based on your camera's firmware.
To locate your camera's firmware version, set the camera to play mode, and then turn it on. Hold down the Func Set button and press the Disp button. A window should appear, identifying your camera's firmware. Look for the number with a letter following it. On my test Canon Powershot SD870 IS, the ID was "Firmware Ver GM1.00C."
Grab an SD Card that you don't mind erasing, and then download and install a flash management utility called Card Tricks. Insert the SD Card into your PC's card reader, and launch Card Tricks. Click the SD Card icon and select your card. Click Format as FAT. Once the formatting is complete, select the card again by clicking the SD Card icon, and then click Make Bootable. Choose Download CHDK, and the software should open a Web page where you can choose your camera model. If more than one version of CHDK is available, match your camera firmware's final letter with the available downloads. Save the zipped file to your Desktop without extracting it.
In Card Tricks, click CHDK-]Card, and select your .zip file. After the status messages disappear, eject the card, and slide the card's physical lock switch to its locked position. Insert the card back into the camera, and power it up. You should see a brief splash screen signifying that CHDK has launched. Now you're ready to activate your Canon's newfound superpowers.