Slow motion with Twixtor: How-to

Like it or not, slow motion sequences in videos are getting more and more popular.

With a regular camera you can achieve a certain slow motion effect with pretty much no problems, especially since many cameras can shoot with 50 frames per second (fps). Since regular film is 25 fps you can slow your sequence down a little bit before you see the choppy effect (where you can see that there are individual pictures being shown).

If you want a more extreme effect, like say Time Warp on Discovery Channel, you would prefer a camera that can shoot lots and lots more fps. Some of the cameras that have this possibility can take as much as several thousand frames per second. Phantom Flex is and example of a special camera intended for slow motion, and can shoot full HD (1920×1080) with up to 2570 fps.

Photron is another example. Now, both these cameras would cost you quite a bit, so are there no other options? Yes, there is.

Twixtor, a plug-in which can be used in many video editing software solutions, is a good alternative if you’re not rich and famous. It costs about $300. If your material is good, with bright and clear shots, Twixtor can help you to estimate the motion between individual frames and achieve a big degree of slow-down without the viewer seeing picture by picture, but instead a seamless, smooth motion.

The video above was shot with a Canon EOS 7D, 50 fps at 1280×720. The shutter speed was at 1/2500, ISO at 1000, and the blender low. The main idea is that you would try to get as many fps and as short shutter speed as possible. This means you need good light conditions. I then slowed it down to 1% in Premiere Pro. No, it’s not perfect – which you can see when it’s hard for the software to predict the motion between the various frames and what’s going on. An example are when the feet are crossing eachother. This can be compensated for in the settings for the plug-in, but can be hard to figure out. Check out the tutorials over at the Twixtor site for some help. You can also find many helpful video tutorials if you search around.

There are some things you need to do that aren’t that logical, but once you get the hang of it it is quick to try out. The big difference in Adobe Premiere Pro CS5 is that you should put the clip you want to slow down in a sequence by itself and add black/empty video after this. The length of the black video should be based on how much you want to slow it all down. Go back to your main sequence, add the slowed down sequence as a clip and add the Twixtor effect on it. Edit the setting to the desired values and render. Experiment with different settings if you’re not getting what you want.

Note that the sound will not be slowed down.

And remember, slowing your material down to 1% speed is an extreme example – something which you would probably not need in many cases. Twixtor works much better if you keep it to a more «sensible» slow-down. It is a big help also when you just want a better slow-down effect than what’s built into editing software.

Anyway, start experimenting – there are free demo versions for you to try out!


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