Sunday, December 6, 2009

CHDK - a Canon PowerShot power user's dream cam come true

I recently purchased the Canon PowerShot SX200 IS as my new main camera. I wanted a digicam which would support both automatic and manual modes to get more seriously into photography.

After thoroughly researching all current digital cameras in the targeted price range, it was the one that always came up as my best match. Here's a link to a highly informative resource (in German):

And it really turned out to be a great cam: With its smart Easy and Auto modes, it couldn't be any easier to use. On the other hand, it includes semi-automatic Tv (Time value) and Av (Aperture value) modes as well as a full Manual mode.

Then I followed a free online course about photography where I learned a lot. Here's the link (in German, too):

So far, so good. But then, equipped with better knowledge, my equipment's limitations suddenly became obvious to me.

Having learned about focal length, depth of field and hyperfocal distance, I couldn't use that knowledge with my camera. It simply didn't display those values in any meaningful way. My hope to do HDR imaging also appeared to be lost since the camera lacked saving RAW images and bracketing. I even thought about getting another camera, possibly a DSLR, although that would have been out of budget.

But then I stumbled upon an acronym in some forum. And now I have a new camera for free. No, I didn't get a new one, I basically upgraded the old one. With a free open source software project called CHDK (Canon Hacker's Development Kit).

This modification is simply installed onto the SD card which is then made bootable. When the camera boots off the card, its firmware is extended with an Alt mode that provides many, many great new features. The camera's actual firmware is not modified physically, the extension is just a program it runs, so it doesn't void the warranty or damage the system. Everything is well documented and easy to set up, and when it's done, it's almost as if you got a new, better cam.

I can't speak highly enough of this project! I can't recommend it highly enough! This is one of the coolest hacks I've ever seen. I'm amazed by how much it adds to an already powerful camera.

Here's what it does for me:
  • Shows zoom value as 35 mm equivalent focal length - unmodified, the cam only showed a zoom bar, without focal length.
  • Shows depth of field (distance of subject, nearest distance in focus, farthest distance in focus, depth of field, and hyperfocal distance) - unmodified, the cam only showed a focus bar, with little information.
  • Adds shortcut to automatically set manual focus to hyperfocal distance - unmodified, hyperfocal distance was pretty much useless, with depth of field information not being displayed.
  • Shows live histogram (before taking a picture) - unmodified, a histogram was only available when viewing an already taken picture.
  • Shows over- and underexposed areas live (before taking a picture) - unmodified, only overexposed areas were shown when viewing the histogram.
  • Optionally saves pictures as RAW/DNG (in addition to JPEG) - unmodified, only the JPEG format was available.
  • Bracketing modes (Tv, Av, MF, and ISO) - unmodified, automatic bracketing wasn't supported.
  • Plus other extras like battery status displayed with remaining charge as a percentage, optical zoom during video recording, and much more - in fact, custom scripts can be loaded which provide even more capabilities and features.
As you can see, if you're a fellow Canon cam owner (PowerShot or not), this is truly something big! I'm rarely that excited about some kind of software, but CHDK certainly deserves all the attention. It's continuously improved by some very skilled and even more generous hackers, so a great big THANK YOU to you all!

Here's a link to the project's wiki where you can get much more information about it:

German-speaking users should also take a look at the German forums here:

There's even a further improved German version, CHDK-DE, check it out there as well:

I'm sure you'll enjoy it. Keep spreading the word. Free open source software is even improving digital camera firmware now! Thank you all very much!

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