I normally hate vertical videos. Why shoot with an upright phone when so many people will watch the finished article on their laptop, TV or PC monitor? After pressing play on a YouTube or Facebook clip, I don't want to see a tiny slither with swathes of black on either side. Slowly, however, I'm starting to appreciate the portrait format. Periscope and Snapchat use vertical video to great effect, and now there's the short movie Impact by French director Jean-Charles Granjon. It's a beautiful snapshot which uses the inherent shape of a vertical video to better express its subject matter: Lionel Franc, a world champion cliff diver plunging into the ocean.