Shooting at a higher frame rate

[Todd Terry]

[Ferguson MacDougal] “How does it look good and normal if at 30fps 1/120 if it should look janky when not slowing down 60fps?”

I don’t know, I’ve never seen action footage where the same exact footage looked great/perfect both at normal speed and slow-mo. Usually (or rather always, in my case) it’s either one or the other.

Very often you’ll see those action plays at normal speed that suddenly slow mo… in the majority of the cases the edit only lets you see a second or so at normal speed before it speed ramps down to slow-mo… not really enough time to notice the narrow-shutter artifacts in the normal-speed footage. You could try to introduce some artificial motion blur in the normal-speed stuff, but that would be a lot of work (tons of layers and masking, etc.), very tedious.

If you are shooting a lot of footage and you know that a significant portion of it (but not sure what parts) will be slow-mo’d, then the only choice really is to shoot at a higher fps and just deal with and live with the narrow shutter look with the normal-speed footage. That’s a lot better than slowing normal-speed footage for fake slow-mo, unless that’s the look you want. Personally I hate the narrow shutter look with a passion (except in rare cases where it is an intended effect) so I always try to shoot at the appropriate frame rate… but maybe it bothers me more than most people, though.

T2

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Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

[Ferguson Macdougal]

Maybe I just don’t have a good eye for it. I’m still new to this stuff.

In this video- https://vimeo.com/244557169

You’ll see mostly regular speed with occasional use of slo-mo. Can you tell what the playback fps is and shutter speed by watching it? Does the regular speed look bad to you?

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[Ryan Elder]

But what if the OP shot at 1/60th shutter speed at 60 fps? Then the shutter speed will not be narrow looking, and you can still have the option of slow motion if the whole movie is shot at 60 fps, wouldn’t you?

The only thing then is, is that their will be more motion blur in the slow motion, but that’s not necessarily a bad thing, is it?

[Andrew Somers]

There are many reasons NOT to shoot at 60fps all the time when you are finishing in 24fps;

1) If you want to playback 60p footage at 24p at “normal”speed, then frames have to be removed, and it is not a 1:1 relationship, so at 24fps some frames are temporally closer together than others, resulting in a juddering motion which you normally do NOT want.

2) Shooting everything at 60 results in a much greater amount of data and storage needed.

3) Your shutter duration at 60 will typically be different than what you want or is optimal for 24.

4) 60 typically requires more light for a given EV due to the shorter shutter duration.

5) Depending on the camera system/type and the type of file you are recording out to, there may be other problems shooting at the higher rate, such as increased compression artifacts.

IN SHORT: especially if your target is 24, shoot everything at 24 that you want to play at 24, and only shoot higher frame rates when you want a slowed-motion effect. This is the kind of thing you should be in touch with before you shoot as a matter of planning.

ALTERNATIVES AND EXCEPTIONS: There are flow field post processes (i.e. “timeWar”, :”Kronos”) that can create a credible slow motion from normal speed elements (depending on the subject matter). These processes CAN also be used to get a better interpolation to make 60 play normally at 24. However, they are not without artifacts and do take a lot of rendering time to complete.

If your target is 30, and your story has a lot of speed ramps/cuts back and forth from normal to slomo, then you might be able to make a case for shooting 60 for all shots for scene where that is needed.

If the target is 24, the equivalent would be shooting in 48, or maybe 72, though I’d expect greater problems in post, including and not limited to audio sync issues.

Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com