Tuesday, March 29, 2011

CHDK: Timelapse To Go

Following on from my previous timelapse work, which was shot in a controlled, studio environment, I really wanted to be able to shoot timelapse outdoors. Capturing changing light and landscape and bringing it to life is fascinating and an obvious extrapolation of still landscape photography. But, the previous timelapse work had been mains powered and laptop controlled; not ideal if you want to work on location, in the hills for example.

Then I found this: chdk.wikia.com

CHDK has been something of a revelation: my G9 (which pretty much goes everywhere with me anyway) can now be set-up and left to shoot timelapse frames for as long as the battery lasts, or there's space on the disk! You can, I know, already shoot 1 or 2 second timelapse movies (here's an old test from a walk across london) on the G9 but they're very limited: only 640x480, pre-compressed as .avi movies, only 1 or 2 second options for timing etc

Loganlea Reservoir from pelicanImages on Vimeo.

I spent a few hours reading through the very helpful forums and getting my head around what is and isn't G9 specific (CHDK works for seemingly all Canon compacts!) so there were a few sequences that have already been deleted and a few more that were technically good but aesthetically rubbish (do you really want to see me eat my dinner in 5 second samples? ;o)

I've now settled on the UltraIntervalometer script for timelapse shooting and I'm getting closer to figuring out which camera modes and time sample rates work best for different lighting situation. The shot above of Loganlea Reservoir in the Pentland Hills outside Edinburgh was shot in Av mode, manually focused to infinity with a time sample of every 5 seconds. Image size was M1 jpegs to allow for post shooting transforms or cropping.

All these frames and control from one G9 sat on a wall: definitely a lot more portable than a full SLR+Laptop+power set-up. Not bad at all.

I learned a lot from shooting this simple setup, for example:
-> 5seconds look a little too quick when played back at 24fps
--> maybe 3 second interval would be better
-> A fully charged battery will last for around 2hrs outdoors
--> this may be temperature dependant though)
-> The default max card size of 2GB is too small
--> I need to dig deeper into the forums to figure out how to get at least a 4GB card to work
-> 0% doesn't mean that the battery is dead!
--> It'll hang in for a few more minutes and shots after that.
-> Take a big jacket, hanging around for >=2hrs can get pretty chilly!

So, lots to learn, in a good way.
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