🎬 Frame Rate & Creative Shutter

Frame Rate is simply how many frames are captured in a second.

  • 24 fps is the traditional frame rate of cinema
  • 30 fps is typical of TV
  • If you want to know the differences between 23.976 and 29.97 visit the “The Technical” section of this course. Here were only concerned with frame rate and its aesthetic impact.
  • Higher frame rates like 60 fps are designed for slow motion if played back at lower frame rates
  • Slower frame rates like 12 fps will appear faster when played back at 24 fps
  • Adventurous and prolific filmmakers have tried higher frame rates for movies though it’s not generally appreciated (see below)

So what can you do with shutter speed creatively? 

  • In photography, shutter is used to freeze a fast-moving subject or obscure a fast-moving subject, reveal more than is visible to the eye in low light (e.g. aurora shots look awesome) and for light painting and light sources moving in an image. Some of these can be accomplished similarly in video, but you’re limited by the frame rate since the shutter open for longer than the duration of one frame.
  • Convey passage of time
  • Make video look staccato, hyper-real and agitated
  • Make video look dreamy and blurred
  • Minimize electronic display banding and flicker by syncing shutter speed with electrical frequency, or do the opposite (e.g. when you see helicopter blades or car tire rims not moving in a video). The most fun I’ve had with this is the old suspension of water video illusion.

High shutter speeds are often used in action shots to accentuate motion. Looks like this:

The ‘jittery’ look of high shutter speed video

Higher shutter speeds lend a ‘staccato’ appearance to moving images, so it’s quite common to leave your shutter at the standard 1/48 of a second. Think Saving Private Ryan or Sherlock fight scenes. It feels a bit hyperreal and agitated. Stop motion videos often suffer from the same problem since each individual frame is taken without movement. There are tools for adding motion blur in post. BlackMagic Resolve and Fusion have these tools built in and they work pretty well. If you’re using Adobe applications, ReVisionFX makes a great plugin called Reel Smart Motion Blur which does the same thing. Computer generated imagery is easier to add motion blur to since the computer already knows the motion of the subject and no “motion vectors” have to be calculated. In After Effects or Fusion, this is what the motion blur toggle is using. It works great for motion graphics. 3D applications also rely on adding motion blur after the render where it’s much faster and more controllable.

The Hobbit notoriously shot at 48 frames per second, but what about shutter speed? Peter himself has the answer: a 270ΒΊ shutter angle. That equates to a 1/64 of a second shutter speed at 48 frames per second. But as far as motion blur is concerned, that’s still 1/64th of a second motion blur, even when projected at 24 frames per second (135ΒΊ at 24 fps). Notice that they didn’t shoot the whole thing at 1/96 due to the “double the frame rate to determine shutter” idea. Instead, they went with something close enough to the ‘standard’ motion blur of 24fps 1/48 that nobody would really notice. The increasing “temporal resolution” of more frames certainly made pans smoother, but it also made the whole thing more “realistic” which wasn’t universally appreciated. This has more to do with frame rate than shutter speed though.

See the “Shutter” section for a look at how shutter speed affects your exposure.