I've read a bit about the f/4 making some noise but I just wanted to confirm that this is normal. I put the camera in Live Mode and shot a couple seconds of video so I could record the sound.
This is basically what it sounds like when taking stills.
i once owned a 300mm f4 IS lens which was much worse. It made a clunking sound when the IS engaged that was loud enough that it attracted the attention of people in the room. That was considered normal I found out. The 70-200mm f4 IS lens is much quieter comparatively IMO.