48fps slowed to 24fps

[Jay Adra]

I have a question which I've researched, but just ended up confused.

I wish to shoot a short film which will be entirely in "slow motion". I want it to have the same aesthetic it would normally have though (24fps at 1/48th shutter).

So I am thinking I should shoot at 48fps with 1/96 shutter and slow 50%? Or do I need to shoot at 48fps with 1/48 shutter still?

Additionally, would this achieve the same look as the traditional 24fps at 1/48? Or is there no way to replicate that look at 48fps?

Lastly, if I wanted to have some scenes play at full speed (not slowed down), i.e. 48fps footage reduced down to 24fps to conform with the project, would the resultant image be the same as normal 24fps footage with 1/48 shutter?

Really appreciate any insights anyone can offer.

Thanks!

 

[Tony Ditata]

If shooting at 48fps than 1/96 shutter is the way to go in order to maintain typical motion. If you shot at 1/48 shutter at 48fps, there would be more motion blur and you wouldn't have crisp slow mo images that have the same type of motion that footage shot in 24fps at 1/48 would have.
If you shot in this way however and wanted to play at normal speed like you mentioned the footage would have a slightly choppy high shutter speed look. Do some tests and see the difference and decide what works best for the project. Hope that helps.

 

[Jay Adra]

That's very helpful Tony, thanks!

And am I understanding correctly that the reason it would look choppier at normal speed is because it was shot at 1/96 shutter, but is being reduced down to 24fps, therefore making it 24fps 1/96?

 

[paulherrin]

what do you mean, highspeed or slowmotion? or high frame rate?

personally, i wouldn't worry so much about the shutter speed, it's always recommended to do some tests and see what's good, or just get out there and start waving the camera around and act like you know how to use it

see also: http://plato.stanford.edu/entries/dewey-aesthetics/

an old wise man from the dreamtime [perhaps - go confirm with the tribes] once said, 'go observe moving water at alternate shutter angles and pay close attention to the healthfulness of the seas and everything in them'

or something along those lines, there's some debate still about verbatim oral tradition and turtles all the way and current matters

 

[Tony Ditata]

That's very helpful Tony, thanks!

And am I understanding correctly that the reason it would look choppier at normal speed is because it was shot at 1/96 shutter, but is being reduced down to 24fps, therefore making it 24fps 1/96?

Yes that's correct. Again give it a try. Shoot a few tests. That look may work for the project but to keep the typical motion we are used to seeing in 24fps film than double the frame rate to get your shutter speed.

 

[Gene Sung]

Hi Jay,

I've had two Sony's so far (FS700 and FS7) so I've had quite a bit slow motion experience. I can say that if you want it to be 24fps real time, you should shoot it in 24fps real time. When shooting slow motion no matter what the shutter angle is 180 or 360, when I speed it up to real time (24fps), many of times it has a bit of stutter to it. Slow motion to 24fps just looks slightly different than regular 24fps no matter what you do.

With real high speed stuff, 120fps +, I find that Reel Smart Motion Blur plug-in helps smooths things out a bit, otherwise it's stutter city.

 

[Marcus Friedlander]

I'm not an expert on this, but I believe leaving your shutter at 180 degrees and changing your FPS (and blackshade to compensate)!will do what you are looking for. Right?

 

[Nick Morrison]

We shoot 48fps and speed it up all the time to 23.98.

One trick we use is to KEEP the shutter at 1/48.

Why? Well - played back at 48fps...1/48 is still fast enough to look "good", especially in shots without TOO much motion (we do a lot of portraits and head turns to camera for ex).

The other advantage...is when sped up 2x to 23.98...the 1/48 then looks "normal", and not as choppy as say 1/96.

Also...we save a stop of light using 1/48 @48fps (vs 1/96)...and sticking to 1/48 also means we keep the same blackshade when flilpping btw 23.98 and 48fps (a huge timesaver, and how we stumbled on this in the first place!).

Hope this helps.

 

[Jay Adra]

Thanks for the input everyone - this helps a lot.

I think I'll just do some tests to see what works best and perhaps shoot a rough pre-vis so I can work out exactly where it'll be playing at full-speed and where it will be half-speed.