Slow Fast Slow is our (free!) app for controlling the speed of videos you shoot on your iPhone. Its typical use is to change the speed of slow motion videos, but there are actually a few non-obvious uses of Slow Fast Slow, making it a useful tool in other contexts.

Converting a slo-mo video to normal speed.
Normal video and Slo-mo video are adjacent to one another in the Camera app mode selector, so it is not uncommon to accidentally shoot a slo-mo video, when all you wanted was a regular video. Slow Fast Slow makes it incredibly easy to convert this video to a normal speed video. Simply import the video, then export it without altering the timeline. It will export as a normal speed video at 30 fps. Easy!

Sharing an uncropped video on Instagram or Vine.
Instagram, famously, displays photos and videos in a square format. There are several apps available for adding letterboxing to your photos, but the same can’t be said for videos. If you shoot a video (slo-mo or otherwise), and don’t want it to be cropped into a square, import into Slow Fast Slow, and then when exporting, choose the “Square (Uncropped)” option. This will keep your video uncropped, with black letterboxes.

Speeding up a Hyperlapse or iOS time-lapse.
Hyperlapse is an incredible app, if only for its stabilization feature. Likewise, the built in iOS time-lapse mode is handy if you want to shoot a time-lapse without fussing with options and settings. Both have limitations, though. Hyperlapse only lets you speed things up to 12x, and the iOS time-lapse mode doesn’t let you control the speed at all. After shooting video in either app, import to Slow Fast Slow to have control over the final speed of your video.