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Playing around with CHDK

I own a Canon Powershot A540, and I’ve been putting it through its paces this summer. There are a few ways in which I’ve sort of hit the limits of its capabilities; for example, I can’t do the typical slow-shutter-speed waterfall photographs because the aperture only goes down to f/8 (although I could probably hack it with a makeshift ND filter or something). Interestingly, the capabilities of these cameras are in part set by the firmware, and so there is an open-source firmware enhancement project called CHDK which aims to both unlock the full featureset of the hardware and augment it with more featureful software.

CHDK has a huge list of features ranging from a file browser to a fancy, live, per-channel histogram to games, but I’m mostly interested in the manual controls and RAW output. After installing it, CHDK allowed me to override many of the settings on my camera to values more extreme than was previously possible. It has a gigantic shutter speed range (something like 2048 s to 1/100,000 s), the aperture can go down to f/16, and the ISO is tweakable by tiny increments over a huge range (which is basically unusable at both ends). Also, I’ve been playing around with saving RAW images (although I purchased a memory card without this in mind, so the number of shots I can take in both RAW and JPEG is pretty limited).

I had installed this before, but gotten rid of it when I didn’t use many of the features. Also, the UI is absolutely terrible (elements on the display tend to collide with other elements, both from the original Canon firmware and elements of CHDK itself). However, I’m going to try to stick it out for a while and use the fancier features to try some new stuff before I get a new camera later this summer (I have my eye on a Canon EOS Rebel XSi). Here’s my first ever attempt at night photography: I stepped outside and took a picture of the street from where I stood, using a 20 s exposure due to CHDK. Yes, I know it’s pretty crappy:

Those street signs are super blown out.

Be back later with pics of Seattle, hopefully including some fireworks.

Tags: canon, chdk, Photography, powershot

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