I’ve been doing more playing with the SmoothCam effect in Final Cut:
What SmoothCam does:
It moves and rotates your source video to smooth a shot. It doesn’t make a shot look like it has been shot on a locked off tripod, it takes large translation, rotation and scale moves and smooths the movements.
As you usually don’t want the edges of your video to be seen when it is smoothed, it gives you the option of scaling your video up so that you don’t see past the edge of the video. That means you should make sure you shoot progressive, and frame to allow for what SmoothCam will do. As some HD video is delivered in 720p format, you can scale up your 1080p video by 50% without any loss in resolution.
The following video shows what is produced if your shutter speed is too low. If you shoot at 25p and your shutter speed in 1/50th, the motion blurs look like distortions:
So use a higher shutter speed that you would normally.
You can also smooth a (very long) series of stills too: