About prank videos

I've seen some carry their iphones around in their hands in some pranks

Did i understand that right they have no clothes on? What the hell kind of prank videos did you watch then if so?

Probably use directional microphones or hidden microphones.

For example - http://www.youtube.com/watch?v=jIFG0cqpdI8

Wireless microphone or just phone/sound recording device (if they don't have money for the first). You can merge the sound with the video later at home.

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