Originally posted by Giklab Unmount the lens and look at the left side of the mount (towards where the grip is) and turn the camera on. You should see a small part vibrate on a metal tube.
Alright, I just tried that and did not see anything move. I did notice a black plastic tab on a thin vertical metal rod in the general vicinity, but it didn't move at all when the camera was switched on or off. I tried this about five times, looking for anything moving between the lens mount and the mirror. Nothing.
I did percieve the sound as clearly coming from the top of the camera, though. It sounds as though it's coming from the speaker, or at least from around there. It should be audible in a quiet setting with the camera at arm's length from your head – at least it is for me.
Edit: I can confirm that the sound seems dampened when covering the speaker hole with my finger.