Advanced Techniques - Hacking Canon Firmware

Supercharge Your Canon Digital Camera with Open-Source CHDK Firmware

from Wired How-To Wiki

ONLY FOR CERTAIN CANON DIGITAL CAMERAS!

It has become apparent that digital cameras have capabilities beyond what is immediately available to the user. On a standard Canon, for example, the fastest shutter speed option offered is 1/1,600 second, but the hardware can actually handle much more than that - up to 1/60,000 of a second.

The Canon Hacker's Development Kit, or knows as CHDK, is an open-source software project that can be loaded on cameras using Canon's DIGIC II or DIGIC III firmware platforms. It unleashes new features including RAW file format, live histogram display, a battery readout, in addition to the ability to run scripted actions on a camera.

The good news is that CHDK does not replace the existing firmware on your Canon, so the process is completely reversible. The existing firmware stays intact, while the CHDK software is loaded on demand from an SD card.

How To Install It

It's best to start with a blank SD card, so if there are pictures on your card, remove them first.

There are numerous incarnations of the CHDK software, different builds incorporating different features. If you don't have a particularly rare camera or unusual needs, the best build to start with is probably the Allbest build, a good all-purpose build that incorporates a majority of features.

Determine which camera model you own, by looking at the model number on the camera. Download the appropriate CHDK package for your digital camera from this site.

Note: The "Ixus" designation is European: what Americans call the Canon SD800, Europeans call the Ixus 850. The filename of the firmware should include both names, e.g. allbest-ixus850_sd800-100e-49.zip.

Also download the "english.lng" language file.

Unzip the zip file. It should contain two files, DISKBOOT.BIN and PS.FIR. Put your SD card in your card reader and copy those files, plus english.lng, to the topmost directory on your card.

Once you've put those files on your card, put the card back in the camera.

How To Use It

Switch the camera into View (not Shoot) mode, and turn it on. When you press the Menu button, you should notice a new menu option: Firm Update. Select this option (remember, it's non-destructive) and the CHDK software will be loaded on your camera, which should reboot itself. Immediately, you'll see a display of battery percentage and storage remaining.

The extra features can be accessed and configured via "Alt mode," an alternate mode into which you toggle by pressing a particular key. On the SD700, it's the Print key; it may be different on your camera. It should be configurable in the Alt menu.

You can tell you're in Alt mode when there's a little "ALT" displayed at the bottom of the screen.

After entering Alt mode, press the Menu key to bring up the menu. This reveals all sorts of options: customizing the on-screen display (called the "OSD"), playing games, you name it. Use the camera's directional keys to navigate the menu.

Play Around

Your camera is now set up to take all kinds of fancy photos. You can do Edgerton-style high-speed digital photography, or low-light high-ISO tricks, or script complex actions. The CHDK wiki includes lots of digital photography tips and tutorials and user-written scripts. Here are some of our favorites:

• Unlimited Interval Shooting - Use your camera for surveillance, or use it to shoot at precise intervals during a lunar eclipse or meteor shower.


• High-Speed Shutter - Use this override option in the AllBest firmware to explore life's littler moments. You can also override the camera's slowest shutter speed settings to shoot exposures of a minute or longer.


• Long Exposure Intervalometer - Take multiple long exposure shots all night, then assemble the shots into your own time lapse videos.


• Shoot better HDR pics with CHDK's auto-bracketing features.

Set CHDK as Your Default

At this point, CHDK is only loaded manually when you select Firm Update as you did above. When you shut the camera off, it'll be gone (although your configuration options are stored in a config file on your card). If you want to have it load automatically every time you turn on the camera, follow these steps:

1. Go to Debug Parameters in the Alt menu, and select "Make card bootable."
2. Turn off the camera, remove the card, and switch its manual switch to Lock position. If your card doesn't lock, you can't auto-boot CHDK, sorry.
3. Put the card back in. Now CHDK will load automatically whenever you turn on the camera. Unlock the card to disable this.