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Shooting documentary Slow motion


Duca Simon Luchini

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Hi everybody, recently I see a fun video about parody about contemporary documentary style:

 

http://nofilmschool.com/2015/09/hilarious-parody-documentary-style-taking-over-internet

 

It is clear that in this case we are talking about a (continuous) LIGHT slow motion and not about an (episodic) EXTREME slow motion.
So, I asked me if in these cases, we have to film at 50, 60 fps to be sure to have a great slow LIGHT motion or if is not important shot at 50, 60 FPS (said 50, 60 are FPS value because this FPS value is available in the most common video cameras) cause we can get the a good slow motion at 24, 25 or 30 fps?
Your experience in this regard? Suggestion?
Many thanks for a reply!

 

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I didn't understand your question. Are you asking what the difference is between 60fps and 30fps slow motion when shooting at a base frame rate of 24/25fps?

 

At 24fps, 30fps is only 1.25x slower than real life, 48fps is 2x, 60fps is 2.5x, 72fps is 3x, 96fps is 4x, and so on. The faster the subject moves, the slower you need to shoot to get a visible effect. Of course, some filmmakers like Martin Scorsese make great use of subtle slow motion effects (in the 22-36fps range).

 

When shooting on film, you had to use some imagination to anticipate what the effect would be, shoot it, have the film processed, and watch the result days later. Now with digital cameras and nonlinear editing tools, you can see what you shot right away so it's quite easy to experiment and get the effect you want. In fact, a good way to preview the effect would be to shoot something at 24/25fps, bring it into Final Cut, Premiere, or any other editor and render a slow motion effect at 1.25x, 2.5x, etc. Then pick the frame rate that you like best and shoot it for real.

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Hi S,

I think I didn't understand your answer... :unsure:

If you shoot at 50 o 60 fps, when you slow in post, you should have many many frame to dale this effect greatly, avoiding frame "flickering". Instead, if you shot at 24/25 fps, when you slow in post, you have really few frames and maybe is hard to avoid frame "flickering". But interesting is what you said about Scorsese's slow motion approach, anyway... if he thought he was slowing the scene, because he didn't shot at 50 or 60 or more fps? I Mean, why in the r 22-36fps range?

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If you shoot at 60fps in-camera, then you don't need to slow down the footage in post. You may have to tell the editing software to play the shot back at 24fps by right clicking on the clip and telling it to 'Intepret as 23.98fps' or something like that, but you don't need to render anything.

 

I'm not sure what you mean by frame flickering, perhaps you mean strobing? Strobing means that the image jumps sharply from frame to frame instead of flowing smoothly. As you say, this would be a result of shooting 24fps and rendering a slow motion effect in post. This happens because you are simply copying each frame twice to get a 2x slow motion effect. So the subject freezes for two frames, then moves for one frame, then freezes again for two frames, and so on. If your goal is to have smooth slow motion, then you should shoot it that way instead of trying to slow down in post.

 

This is why Scorsese is a master filmmaker - because he understands how shooting variable frame rates in-camera can create a visceral emotional effect for the audience. For example, in "Raging Bull" he speeds up parts of the boxing scenes by shooting at 20-22fps, so that when played back at 24fps the action seems faster than real life, but not unrealistically so. The punches seem to hurt more because they come so fast.

 

In "Goodfellas" there is a shot where Robert Deniro's character Jimmy Conway decides to kill someone. The shot slowly pushes into his close up as he smokes a cigarette at the bar and watches the man who is about to die. The camera ramps from 24fps to something like 32-36fps, very slight slow motion. It's a very subtle effect, but along with the acting and music cues it helps the audience understand that Jimmy is not thinking about the present - he's planning for the future and it's gonna be bad. This kind of emotional manipulation is pretty advanced level filmmaking.

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