60fps timelines

Hello all, something  that occurred to me recently… I have seen so many topics about using 60fps footage in a 24 fps timeline.  Occurred to me that why not just shoot at 60fps and drop it in a 60fps timeline?  If I need to slow it down, I can slow to 24fps (40%} and still get smooth slo mo.  I did an experiment and I tried this… I think it turned out just fine!  I’m using the 180° shutter rule, so my footage still has decent motion blur.  Can anyone think of any reason this is a bad idea?

Depends on the amount of movement in the shot, and what you're going to. What you are doing will look really bad on a screen in a movie theater where imperfections are exaggerated. But shooing 60/editing 24 simply gives you all original frames, nothing faked, the absolute best quality is carried through the entire workflow pipeline. If there's not too much movement or changing of lighting, what you're doing can work out OK. But there are situations where it will fall apart.

Thanks for the feedback, Ben.  But can you be a bit more specific on what you mean?  For example, you say shooting 60/editing 24 gives you all original frames.  But editing 24 means I'm dropping 1-2 frames per 3. There must be a continuity loss in doing so (unless you conform and frame blend your 60 footage, but thats a computer deciding what each frame should look like.).  So I'm not sure if I understand thats the best quality, I would think the best quality is what came out of the camera.  Also, can you give me examples of where this process would fall apart?

Itstonybabyvlog wrote:

....why not just shoot at 60fps and drop it in a 60fps timeline?...I’m using the 180° shutter rule, so my footage still has decent motion blur. Can anyone think of any reason this is a bad idea?

Here are four issues:(1) Overall "look" of 60 fps vs 24 fps. For a skateboard video 60 fps may be OK. For serious production 24 fps often looks better. This videographer is discussing 120 fps but he covers the 24 vs 60 vs 120 fps well and shows practical examples:

(2) Problem of mixing frame rates in a 24 fps timeline. If you are doing a little private video it's less an issue. But if you are shooting something that must be combined with material from other people -- OR which might later be used in a 24 fps production, then the issue of mixing frame rates exists. Gerald Undone discusses this here: https://youtu.be/qAVfIQ2G7Io

(3) Storage and lighting requirements for high frame rate material: 60 fps at 180 degree shutter will take 1.5 stops (300%) more light to produce, and at the same compression ratio will take 2.5 times more data. If your data is duplicated for safety, multiply that space penalty by another 2x. If it's being uploaded that will take significantly.

(4) Editing smoothness and machine requirements: since 60 fps is 2.5 times the frames per second as 24, it requires 2.5 times the computing power to decode that at the same playback speed. If a low-compression codec like ProRes, that reduces the compute burden but it then takes 2.5 times the I/O.

you're going to have a 60fps video when you export though. your timeline is 60p. slow your 60p footage to 40% if you want, but it's still playing back 60 frames a second. you're not making anything 24p at that point. it's math. go ahead and do it and go frame by frame. you're getting duplicate frames all over the place. it's not smooth. if you think it looks smooth you need to do a hard comparison between putting 60p in a 60p timeline and slowing it down 40% and watching it back. pay attention. it's jittery. it's not smooth. go frame by frame. duplicate frames everywhere. it's all over the place. it's jarring.

now make a 24p timeline, drop the 60p in it and set it to 40%. it's smooth. every frame is accounted for, nothing is duplicated, nothing is skipped. you're smoothly playing back all frames. and it's also playing back at 24p on your computer because that's what your project is set to.

your 60p timeline is always playing back at 60p. doesn't matter how fast or slow you make your footage, it's a 60p timeline, it will play back at 60p. it will duplicate or drop frames if it needs to to make it it play back at 60p.

Hello, and thank you to everyone that replied to this post! This is an update:

So I have more or less taken the advice of most of you here, and shoot at 60fps/edit at 60fps. I find the quality of the video is just as good in a 60 timeline as it is I a 24 timeline shot at 24 fps. In short, edit in the frame rate you shot in, if at all possible.

When you can't edit in the same frame rate, I find the best option is as follows:

in a 24fps timeline, take your 60fps and use "rate conform" tool (FCPX) and use optical flow to get your 60 frames chopped down to 24, or if using slow mo, just slow to 40% and you got some nice, smooth slow mo, because your still using all the frames at 40% speed (60fps x 40% = 24).

in a 60fps Timeline, the only thing I have to worry about is the slow mo. But Brady said it would be jittery. Actually, I don't find that at all, I can slow my 60fps footage down to 40% in a 60fps timeline, and it still looks fine. I believe that is because, while what Brady says is technically correct, you are getting duplicate frames every 2.5 frames, the total time it takes to show those frames is exactly the same as the time it takes to show 24fps in a 24fps timeline. Therefore, even though there are duplicate frames created in the 60fps timeline, those duplicate frames get overall less view time than the equivalent frames in a 24fps timeline. So at the end of the day, you get exactly the same image, the same pie as it were, just instead of being cut into 4 pieces, its cut into 10 pieces. But it still looks like the same pie.

I hope this contributes a bit more to anyone who has viewed this post with the same question I originally had, and thank you again to everyone for your participation! This forum is a great resource for aspiring editors!