Canon 550D 7x Magnification crop mode. 28-135mm lens.
iMovie on an iMac.
The quality of this crop mode is not particularly good. Its a very small size. As you will see there are also problems with the lens moving in the wind, even though the tripod was a substantial one and everything was bolted down.
The crop is amazing though. This is shot at the equivalent of something like a 1500mm lens (in 35mm terms) I suspect though its probably better to shoot in full HD and crop that.
For more footage with the 550D see:-