Wednesday, July 02, 2008

Real-Life High Dynamic Range Lighting

I've been a sucker for HDR in gaming for a while now. So when I saw mention on Hack a Day about turning your point-and-shoot camera into a full-featured model that allows you to do stop-motion and high dynamic range photography my curiosity was piqued.

The Stuck In Customs HDR Tutorial gives a good reason why HDR photography can be so appealing: our eye adjusts constantly as it is observing its environment, quickly dilating and contracting the pupil to modify the range of light and color hitting the retina. HDR photography does the same thing, re-sampling the image to take in a varying amount of exposure and light at different depths of field.

Hack a Day turned me on to using the CHDK firmware add-on with a Canon SD870 IS. The CHDK add-on software allowed me to do exposure bracketing in continuous shooting mode.

Luckily HDR photography is all the rage lately, so I even had a Grumpy Editor's guide to HDR with Linux. It was great - it introduced me to PFScalibration and Hugin's image alignment, which are both nicely wrapped together in the fantastically easy to use Qtpfsgui toolkit.

Of course I had to turn the flash off and lower the resolution (to allow the continuous mode to write to the SD card faster), but in the end I had a perfect stack of images at varying exposures to import into Qtpfsgui. A tree turns into something more provocative pretty quickly:



I was amazed at the quality of open-source options for photography - Qtpfsgui was great for HDR, and Rawstudio was even more fantastic in dealing with my RAW digital negatives. The SD870 IS doesn't have native RAW file support, but thanks to CHDK and DNG4PS-2 I was able to quickly pull DNG files off of my SD card and start editing them in Rawstudio.

Unfortunately I don't have much if any time to try out new things, but this was a pretty pleasant diversion for the evening.

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