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I always see people taking pictures with light designs behind them on Facebook. I don't know much about how this process works but I'm guessing it has to do with the camera slowing down so if you move some sort of light around, it'll leave a light trail? Anyway, my friend told me it took him hours to get one photo right...If that were the case, I wonder how long this video took to make.
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http://www.youtube.com/watch?v=KaehTtNFGGs
u should try it with the other posters
i can't imagine how much time it took them to do this
pretty sure they didn't use the method you're thinking of...
aMAZING.