Slow Motion Experiment in 120FPS

[Nikonair]

I decided to try an experiment shooting in 120FPS, 1080p for the first time. Now I had thought that this would enable me to run it at normal speed in my editor (Filmora9) and then slow down selected potions at, say, one quarter speed. However, it seems that it plays back at 30 FPS by default, resulting in the whole clip being at a quarter speed. Is that how it works?

Therefore I assume that you have to speed up the footage by a factor of 4 to return it to "normal" speed and then slow down the portions required to be displayed in slow motion.

Am I correct in this thinking, and presumption of workflow?

 

[Deleted member 94047]

However, it seems that it plays back at 30 FPS by default, resulting in the whole clip being at a quarter speed. Is that how it works?

You got the basics right. Shoot at 120fps, play back at 30; that should give you a quarter speed slow mo; but not if the editing software is dropping the extra frames. In the later case, you will just get a normal speed playback with the extra 90 frames dropped. Unfortunately, I have no experience working with the software you are using.

 

[Nikonair]

You got the basics right. Shoot at 120fps, play back at 30; that should give you a quarter speed slow mo; but not if the editing software is dropping the extra frames. In the later case, you will just get a normal speed playback with the extra 90 frames dropped. Unfortunately, I have no experience working with the software you are using.

Thankyou for that confirmation.
The software is certainly playing it back at 1/4 speed, so I don't think it's dropping the "extra" frames. Obviousy there is a lot more data for the software to deal with so any editing presumably is going to take quite a bit longer, but I will play around with it a bit more and see if I can make sense of the workflow and decide oif it is dooable without a ot of extra PITA.

 

[Dave Maine]

Most NLEs will read the metadata for the frame rate shot In the video file. It will often choose to play it at the frame rate of the project it is used in. The speed controls and key frames can be used to divide the clip to play at different speeds for different sections. You are not limited to just 2 speeds, you can pick any for each defined section.

 

[Deleted member 94047]

Thankyou for that confirmation.
The software is certainly playing it back at 1/4 speed, so I don't think it's dropping the "extra" frames. Obviousy there is a lot more data for the software to deal with so any editing presumably is going to take quite a bit longer, but I will play around with it a bit more and see if I can make sense of the workflow and decide oif it is dooable without a ot of extra PITA.

I use Davinci Resolve for editing. If I wanted to do what you are trying to in that I would go about it in this way.

1. Ensure that the timeline is set for 120 fps
2. Import the clip(s) in to the timeline
3. Identify the moments I want to slow down and either insert speed control markers or cut the slow mo scenes in to separate clips
4. Set the playback speed of the slow mo scenes to the desired speed (either 60 or 30fps)

You have to figure out how to do this with the editing software you are using. Wish I could give you a more practical guide but I have never used Filmora. Perhaps someone who has can chime in.