Frame Rate & Shutter

Frame rate decides how time behaves. Shutter decides how motion looks inside each frame. Together they produce the thing audiences call "filmic" without ever being able to name it.

Frame rate

Cinema's traditional rate is 24 frames per second; 25fps is standard for UK and European broadcast. Shooting faster than the playback rate stretches time; shooting slower compresses it.

Shot atPlayed atResultUsed for
24 fps24 fpsReal timeThe default. Everything unless there's a reason.
48 fps24 fps2× slow motionWeight, grace, a beat held open
120 fps24 fps5× slow motionImpact, destruction, dream logic
12 fps24 fps2× fast motionComedy, frenzy, time passing
1 frame / few sec24 fpsTime-lapseDays, weather, cities breathing

Shutter angle

The shutter controls how long each frame is exposed, and therefore how much motion blur it collects. The traditional 180-degree shutter rule sets the shutter to roughly double the frame rate (1/48 or 1/50 of a second at 24/25fps), which produces the natural motion blur audiences associate with film.

Three rotary shutter discs showing 45, 180 and 360 degree openings and the motion blur each produces 45° staccato, jittery 180° natural motion blur 360° smeared, dreamlike
The lit wedge is the portion of each frame's cycle during which the sensor is actually exposed. Narrower opening, less blur, more strobing. A much faster shutter creates the jittery look used in the beach landing of Saving Private Ryan.
45° shutterDiscrete steps. The eye sees each frame as a separate position.
180° shutterBlur that matches what the eye expects from movement.
360° shutterLong smears. Hazy, unstable, unreal.
Maths

Shutter speed = 1 ÷ (frame rate × 2). At 24fps that is 1/48s; at 25fps, 1/50s; at 60fps, 1/120s. Every camera that expresses shutter in degrees instead is doing this conversion for you, which is why degrees are the more portable way to think.

Rule

Break the 180° rule for texture, not for exposure. If you are closing the shutter because the image is too bright, use an ND filter instead. Otherwise you are changing the feel of the movie to solve a lighting problem.

Cinematography & Mise-en-Scène cheat sheets · built from The Foundations of Cinematography and Mise-en-Scène.