The slow motion effect is the result of video that’s captured at a very high frame rate, and then slowed down. This allows you to have video with reduced speed without any herky-jerkyness. The end result is a professional quality slow motion effect that you and your friends will love.
If you watched Apple’s media event, you will probably know that Slo-Mo mode captures video at a brisk 120 fps, so when you watch the video as you record through the view finder, everything seems really fast and a bit jerky. Once you finish shooting, you can use a scrubber that’s not unlike the editing scrubber used for cutting video. The scrubber allows you to adjust the in and out points for the slow motion effect.