Cinematography : Slow motion, shutter angle, frame rates and the perception of these by Vital Butinar

Vital Butinar

Slow motion, shutter angle, frame rates and the perception of these

Hi guys.

I've been a little absent lately due to some stuff happening around us these days but I finally found some time to think about some things and write something.

Well the first thing is something really funny I thought about a few days ago.

My dad, my mom, my friends mom and quite a few people I know can't distinguish (or at least can't identify) the difference in an image shot at 24, 25, 30, 50, 60 or even 120 fps, let alone the difference between a 180° and 360° shutter angle.

They also can's see much of a difference between SD, HD, 4K resolution or something shot in a studio vs. something shot outside, not to mention something shot on a green screen.

But my mother in law, who is a costume designer can tell the difference.

This is really funny to me, until I actually got rid of my biased view from knowing a lot more about these things than they do. All of this is OK because they simply know what they like and most of the time I've deduced that it has more to do with the content than with how it looks.

I remember having conversations about this exact thing with a buddy of mine from more than 20 years ago when we talked about this and now I finally foundered some things out.

I was thinking about slow motion and how I thought that it might be way overused lately because people are using it just to make something look good and not using it enough to convey the story.

Which is my personal view, not to say that slow motion doesn't look good and can't be used. I just feel that it should be used where needed.

Well I have this friend and he's a videographer and I use the term videographer because he shoot's video and here's the difference to me. A videographer is someone who shoots a lot of video and tries to figures out what to do with it later but a cinematographer is a someone who figures out what to shoot in advanced.

Now he shoots almost everything in 60 or even higher frame rates so that he has the ability to do "cool looking" slow motion shots in post.

I've had some conversations with in the past about shutter angles and slow motion, where something shot in 60 fps might have a different feel to something shot at 24 or 25 fps.

So it made me thing is it all more or less simple than I thought.

When I'm shooting something and it's being produced in 24 fps, the majority will obviously be shot in 24 fps. But shots that we decide to have in slow motion will usually be shot in a higher frame rate.

Just for safety I always like to duplicate these shots and shoot them at the normal frame rate, as well as in slow motion if I decide in post not to use the slow motion shots.

Some time ago it got me thinking that if we're shooting something in 50 fps and it will be played back on 24 fps, that we'd need to account for the slowed down motion blur and needed a shutter angle that compliments the slowed down speed not the shooting speed.

So the 180° shutter angle needed to be applied to the slowed down footage and had to be calculated to the let's say 50 fps shooting speed.

But this got me thinking if I was over thinking everything (no pawn intend) and do the differences in shutter angle really even do make a difference.

And after researching everything I came to a really simple conclusion.

It makes a difference only when you're shooting at a higher frame rate and then not slowing it down in post. So if you shoot at 48 fps and then just slap it on a 24 fps timeline it might look weird because the shutter angle si based of the 48 fps. But whenever you slow down any kind of footage the motion blur becomes less important because the image is slowed down anyway.

What in my opinion is a lot more important is if the slowed down image plays a role in the narrative of the entire composition.

Like I said slow motions is cool but if it's used for moving the story along.

So I guess my dad, mom and my friends mom are a lot more in tune to everything because they're focusing on the story and not on the technical side of whatever they're watching.

So here's my question do you guys get hung up on the technical side or does it even matter when you're watching something?

Where's the tipping point when the narrative of a film takes precedence over the quality of the image?

Here's an interesting video I found comparing frame rates and shutter angles.

https://www.youtube.com/watch?v=3EpRUq6Qpo4

Karen "Kay" Ross

Ooo, yes, love it! Imma go back and watch this a few times...

Vital Butinar

Exactly Karen "Kay" Ross. I was apparently over thinking something that in fact doesn't matter that much. But at the same time I was right when shooting at normal frame rate for safety.

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