victorengel said:
Those are a variety of flashes. I first noticed from the inconsistent color of the output. In the making of video, you get a good view of the equipment.
http://www.youtube.com/watch?v=_lGmO6eq9gM&feature=related
I'm guessing someone put the word out that they needed to borrow a bunch of cameras and flashes. Probably 250 willing participants lent theirs for the shoot.
In that video you see that they put a little circuit at the back of each flash. To me that means that the cameras are really used only as stands, not even as cold shoes. In the footnote they mention that they went through arduinos, which is a very cheap way to generate simple 1/0 digital output, for example to drive LEDs. You can buy open hardware kits with software and everything for under $100.
http://evilmadscience.com/productsmenu/tinykitlist/75
If instead of LEDs you connect a little driver for the flash to this circuit you are home for about $200-$300 plus rental of the cameras (which you don't even use) and flashes. Depending on how popular the band they are in Japan, Canon Marketing should have been more than happy to supply these, maybe even in a Canon warehouse
what impresses me more is how fast the flashes regenerate. Some must be firing several times a second. I guess the output per flash must have been tuned way down, also to not blind the camera that is looking straight into the flash unit.
I think it is cool - even if I don't like the music.