Unlock Advanced Features on Your Canon Digital Camera
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.
Shoot RAW to Save the Complete Picture
Your camera processes images a few times in order to spit out JPEGs, compressing and converting the native data that it captures. Even if you set it to record a JPEG at the highest size and in the highest quality, you'll still lose details compared to the camera hardware's inherent ability. RAW pictures--most common on DSLRs--save files in the native format of each specific camera's image sensor. This means that the photos are less compatible with software in general, since the RAW format varies. But the trade-off is that you can process popular camera file formats on a PC, instead of relying on the camera to set white balance and other variables permanently when saving to a JPEG.
On your camera, enter Alt mode by pushing Direct Print or Shortcut. Push the Menu button. Navigate to 'RAW Parameters', activate Save RAW, and you'll see a dot confirming the choice. Push the Menu button again, and exit Alt mode using the same button that you used to enter it. Now a RAW counter should float over your camera's regular remaining-photos countdown, helping you keep track of space for these bigger files. On most cameras, you can toggle RAW mode by holding the shutter halfway, and pressing the joystick to the right.
Apple's Aperture, Adobe's Lightroom, and other photo software can natively read the files from most cameras that have RAW saving built-in. At press time, however, these wouldn't read the unconventional RAW images that we shot using CHDK; you'll need to use a different tool.
I like making simple edits on a PC or Mac with PhotoLine, which natively recognized the files in my tests. Alternatively, you can use other software to alter these true RAW files minimally into DNG images that retain RAW data while becoming compatible with standard image editors. DNG4PS-2, RawTherepee, and UFRaw are good options.
Add a Live Histogram
Your camera likely lets you review a histogram after you take photos, showing the graphed curves that represent color and exposure. If the curve is squished to the left and leaves empty space on the right, for example, your photo is probably too dark and underexposed. If the curve shows values across the entire graph, your image has captured a dynamic range, maximizing the possible highs and lows.
Those details are great for reviewing shots or editing in Photoshop, but they can be even more helpful as live feedback when you are composing photos. Many high-end cameras show live histogram details, but your point-and-shoot probably doesn't. The CHDK software can add that feature.
With CHDK running, enter Alt mode, and push your camera's Menu button. Navigate to Histogram Parameters, and change it to Show Live Histogram [Always]. Push Menu again, and exit Alt mode. Most cameras let you instantly toggle the live histogram by holding the shutter halfway down and pushing the joystick down.
Now you can track exposure and details while composing a shot. Especially in manual modes, you'll typically want to make the curve spread across the entire graph for perfect exposure. Note that in some situations, such as at night, the curve will still favor one side the the graph.
Take Long-Exposure Photos
Some photos look best with long exposures that your camera may not be able to capture natively. For example, you can shoot images of stars or dark scenes by keeping the shutter open longer, capturing more light. You could even shoot a 30-second exposure of a city at night, turning a car's brake lights into wispy red streaks.
Camera companies rarely allow this level of control in models below the DSLR level, but the CHDK software can unlock these effects on your Canon point-and-shoot. Just be sure to use a tripod in most situations, since the camera has to remain perfectly steady.
Enter Alt mode, push the Menu button, and choose Extra Photo Operations. Pick Override shutter speed. From here, you can set extremely long exposures--or set up shorter exposures than your camera might normally support. Your camera might be physically unable to achieve some of the quickest available speeds, but the longest times should be no problem. Set the Value Factor to 1, push Menu, and leave Alt mode. (To turn the shutter override off, return to this menu and choose Off.) Now your pictures will use a shutter length that you select from a list, rather than relying on the camera to set its own speed automatically.
Automate Advanced Tasks
CHDK offers an impressive bump to your camera's built-in features, but you can obtain even more options through its scripting language. You save these scripts to the SD Card from a PC, and once installed they can execute several commands--such as exposure bracketing, where the camera automatically captures a series of differently exposed pictures. With that process, for example, you can shoot a series of photos to produce into a stunningly detailed High Dynamic Range scene, all with a single press of the shutter.
One of my favorite scripts sets time-lapse recordings. This tool will automatically fire your camera shutter on an interval that you select. Later, on a PC, you can import the individual photos into a video editor, and create sped-up shots of flowers opening, street traffic, and other progressive scenes.
Scripts are written in a version of BASIC. You can download many of them through the CHDK Web site. Visit this Web page for a time-lapse script, and just copy the BASIC text from the gray box. Paste the text in a plain-text editor, and save the file as 'ult_intervl.bas' in your SD Card's Scripts folder.
Insert the card into your camera, enter Alt mode, push the Menu button, and select Scripting parameters. Choose Load script from file..., navigate to the script, and select it. In the script menu, you can change some of the variables--the 'Script parameters'--to make it ideal for time-lapse photos.
The "delay" settings cause the camera to wait a fixed amount of time until your first shot is taken. I usually leave that off and then set a total number of shots that I would like to record. The "interval" settings are the most important because they govern the pause between photos. For fast-moving scenes, such as a busy sidewalk, I might wait just a few seconds. For slow scenes, such as stars drifting in the sky, I would set it to wait a minute or more.
Set the camera on a tripod or in another stationary position. Push the camera's Menu button, but stay in Alt mode. Push the shutter button to activate the script. When you're finished, leave Alt mode to go back to regular shooting.