Mixing frame rates and speed

[Eirik26622085a1n7]

Hi,
I am having an issue working with different fps on footage and timeline. If I import a 50fps clip into a 25fps timeline the 50fps clip will not look good. Motions, like paning and tilting will flimmer, and not be smooth. Ive tried different settings, optical flow etc, but nothing seems to help here. Is there a way to make a 50fps clip look smooth in a 25 fps timeline?

I recorded the footage in 50fps because I want some of it - not all - to be in slow motion. I figured capturing in 50fps and then working in a 25fps timeline would be the best way. Appears not so.

However my experience from this is as follows:
- If the 50fps should be smooth you have to work in a 50 fps timeline.
- If you want a slow-motion clip you should create a new timeline - 25 fps - interpret the footage you want to slow down from 50fps to 25fps, and place it in the 25 fps timeline (this will make a smooth slow-motion). Then place this entire timeline (25fps) into the 50 fps timeline. This seems to work ok. 

This does however feel like a very tidious work around, and I believe there is another solution? Help is much appreciated!

[Kevin-Monahan]

Hi @Eirik26622085a1n7,

I read your note. What you might try is setting the speed to 50% in the project panel (use Optical Flow), then edit it into your 25fps Timeline. Does that work? Let us know.

Thanks,

Kevin

[Eirik26622085a1n7]

Hi Kevin,

The problem is not to get the 50p clip to work in slow motion.
The problem is that putting a 50p clip on a 25p timeline, with regular speed, does not give good results. In theory I thought this should work fine, but it doesnt. If I want my 50p clip to be smooth, i need to put it in a 50p timeline. Do you know why?

thanks, 
Eirik

[Eirik26622085a1n7 · Accepted solution]

So i figured it out.
this is the source: https://www.pauljoy.com/2022/01/180-shutter-angle-why-i-dont-use-it-for-50-60p/
I shot the 50p footage with a 180 angle (shutter 1/100), which doesnt work in a 25p timeline - this will result in a a 360 angle when converting the 50p clip to 25p - which is not the correct motion blur, and thus the clip looks bad.

from the article:

360° Shutter for 50p

If I’m shooting at 50p knowing that some of my footage will be used for normal speed playback and some will be 50% slow-mo I’ll generally choose a 360° shutter of 1/50th. The result is that any clip played back at normal speed on a 25p timeline will have the equivalent of 180° shutter angle, ie each frame is exposed for 1/50th of a second.

The compromise with this approach is that any clips slowed down to 50% on the 25p timeline will have a 360° shutter angle with more motion blur than usual. The thing is though, because these clips are slowed down to half speed you rarely notice and in some ways it can make the slow motion footage look even smoother!