Thanks Vic, the video was shot with a GoPro helmet cam, which my older son uses for his BMX tricks (hence the fisheye effect, which they like)
The wobbly mast
and bendy shrouds effect worried me at first, but I got used to it.
It can be set to shoot continuous video, intermittent stills or both simultaneously.
Stills were standard Pentax Optio 6MP digital
PS I'm not sure why there are two click-on video frames in my thread starter. I'm sure watching it once is enough for most people (not for me though!)