Higher Frame Rate vs Higher Shutter Speed

PerroneFord

PerroneFord

Deals in Lead
In reading an article in ASC, something struck me as interesting, and I'd like to ask those of you who may have done this.

What is the effect of shooting much higher frame rates versus using a higher shutter speed? And I don't necessarily mean shooting it for the purpose of over-cranking, but to play back at it's native frame rate.

I'm really not sure how this would be accomplished with film, but it seems possible with video.
 
Using higher frame rates to playback at normal speed is regular slow motion.

Shooting with a high shutter speed is merely a different, more stuttery look.
 
I'm not talking about playing back an normal frame rate. I am talking about playing back at the frame rate it was shot at.
 
24fps @ 24fps = "the film look"

Shooting at a higher frame rate, 60fps @ 60fps, = "the video look"

We can't really detect any motion increases above somewhere around 60 to 72fps, so going much faster than that (for playback at that speed) won't do anything for you.

You can test this easily on an HVX, put it in 720/60P mode and FILM CAM and then change the frame rate; you can see anywhere from 12fps played at 12fps, up to 60fps played at 60fps.

As for shutter speed, it's all about the blur, the faster the shutter speed the less blur there is. You can test that on any camcorder.
 
Yea, I've played with the shutter speed changing, and I understand that well, especially coming from a still background and sports photography.

What got me on this path was reading about "Mongol" where the discussion was about shooting at 100 or 150fps instead of shooting higher shutter speeds. It made me wonder why a cinematographer would choose one over the other, and not necessarily from a sense of overcranking to get a smooth slowdown.
 
PerroneFord said:
Yea, I've played with the shutter speed changing, and I understand that well, especially coming from a still background and sports photography.

What got me on this path was reading about "Mongol" where the discussion was about shooting at 100 or 150fps instead of shooting higher shutter speeds. It made me wonder why a cinematographer would choose one over the other, and not necessarily from a sense of overcranking to get a smooth slowdown.
Click to expand...


The frame rate sets the number of samples per second. Higher frame rate will have more than lower... I think that's obvious. Now, shutter speed only governs how long the light is impinging upon the sensor or film. Less time, less motion blur. But the frame rate will set how many samples one has, no matter how fast the shuttterspeed.

In 'quick' action, there is a strobing effect of things that are moving parallel to the film or sensor plane(*). So at 24 fps one has more strobing than at 100 or 150. Once the higher frame rate material is aquired, processing can performed to 'average' out in such a way as to minimize the strobing effect at the ultimate display rate of 24 fps.

(*) It also occurs when the motion is directly towards or away from the film or sensor plane, but it is less noticeable.
 
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