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where did you read that? Thats very interesting.

I just found this. Worth it:

https://wipster.io/blog/debunking-the-180-degree-shutter-rule

 I want to film everything at 60fps. I want the final video running at 24fps.

No, if you want a stutter free cadence, use exact halves and doubles.

120, 60, 30 etc.

Motion at 24p from 60p source will stumble or blur, depending how you set resample.

 

Motion at 24p from 60p source will stumble or blur, depending how you set resample.

Isn't it supposed that blur and stumble is regulated by the shutter speed primarily and secondly by resampling (or other aspects of the software)?

I'm shooting at 60fps with a speed of 1/120, but when interpreting it at 24fps, it gives me a staccato effect. As far as I understand, this rather than being related to the resampling method or using exact halves or doubles, is related to the fact that it has been shot with a shutter speed of 1/120, when a 24fps video should be shot with a speed of 1/50 to give that "natural" or "cinematographic" motion blur. This is why I am trying to correct these stumbles by recording at 60fps with a speed of 1/60, breaking the shutter rule.

Could you explain more about the exact halves and doubles? I would love to read a little more about it.

You should also read this article: https://wipster.io/blog/debunking-the-180-degree-shutter-rule

I would love to know your opinion about it.

Shooting 60p @ 1/60th is a good idea. If you put it on a 24p timeline, you get a nice EVEN 40% slow motion that looks natural (no resampling is necessary. 60 = 24 + 24 + 12, so you get 2.5 seconds for every 1 second.)

Go for it!

PS The 180 degree "rule" is not a technical rule, it is an heuristic. (i.e. a "rule of thumb") that is meant to be broken when you know how. Look at the opening beach scenes of Saving Private Ryan for a theatrical example of breaking the rule.

60/30 = 2/1. Every other frame will be dropped, but preserve smooth cadence.

60/24 = 5/2. Two out of 10 frames will not  be dropped, resulting in a stutter cadence or blur if resampled.

Twixtor ($) is an alternative.

use exact halves and doubles.

Ok, so lets say Im shooting 50fps @ 1/100 and I want my final video at 25fps. How can I avoid the chopped movement caused by the 1/100? The only idea that comes to my mind (as well as using some plugin or motion blur function in the software) is to set my shutter speed to 1/50 to have a nice motion blur in the final result. But I don't know if that will allow me to make slow mo if necessary

Sir, I am not addressing shutter speed. How sharp or how blurred you prefer your frames is your business.

I am referring to least common multiples, which you may have forgotten.

Starting with 60 Skittles, put an equal number in 24 paper cups. Does it work?

If not, the cadence will stutter or blur depending on your resample mode.

There's your answer.

If you are shooting 60p for slow motion on 24p timeline, then there is no problem. If you are trying to shoot everything in 60p and leave some of it as normal 1x speed, then it has to drop frames and may look a little weird on a 24p timeline (depends on material) so 30p timeline would be better, as Musicvid has explained. You should test and see.

Sir, I am not addressing shutter speed. How sharp or how blurred you prefer your frames is your business.

I know you're not talking about the shutter speed, and that's the problem. You're missing the original point of my post.

When you're doing trial shots of your ceiling fan (assuming you have one) try using a shutter speed slower than your framerate e.g. 1/25 sec at 50 fps. Yes it can be done and my PAL Canon goes down to 1/6 sec at 25 or 50 fps. It's achieved by duplicating frames.

You're missing the original point of my post.

Actually I understand your question quite well. And I agree, shutter speed should be considered -- not first but second, after prescribing an even frame cadence.

As @john_dennis says, the 180º rule isn't a rule, however adding a bit of blur in post is a recognized and valid technique with no downside that I can see. It can even cure some low-percentage speedup or slowdown artifacts such as syncing a dance piece.

None of that, however, affects the "real" rule of frame rate divisibility for smooth cadence. Depending on the source, either it bothers you or it doesn't.

If, as Eric suggests, you are less concerned with having an even order of drops and dupes in the output, then choose a resample mode that suits your eyes.

I'll have a little demo for you perhaps later today.

Source 60p no resample no blur

60p ⇒ 60p 

60p ⇒ 30p

60p ⇒ 24p

60p ⇒ 24p-Force-Resample

@Musicvid That is very valuable information, I appreciate it. Next time I'll use 50fps to convert it to 25fps ... and I'll shoot it at 1/50 to see what kind of motion blur it provides, at normal speed and slow mo.

If not, the cadence will stutter or blur depending on your resample mode.

What type of resampleo provides one or the other?

When you're doing trial shots of your ceiling fan (assuming you have one) try using a shutter speed slower than your framerate e.g. 1/25 sec at 50 fps.

@EricLNZ I'm using a Fujifilm x-t30 and does not provide that option. What ould be the use of film like that?