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Shutter angle ↔ shutter speed
Convert between shutter angle and shutter speed for any frame rate, see the motion-blur look you'll get, and avoid flicker under artificial light. Formula: shutter speed = angle ÷ (360 × fps).
Common shutter angles
| Angle | Speed @24fps | Look |
|---|---|---|
| 360° | 1/24 s | Max motion blur, dreamy |
| 180° | 1/48 s | Natural — the standard |
| 172.8° | 1/50 s | 180°-equivalent, flicker-safe at 50 Hz |
| 90° | 1/96 s | Crisp, slightly staccato |
| 45° | 1/192 s | Sharp, gritty (battle scenes) |
Flicker under artificial light
Lights pulse at twice the mains frequency. To avoid banding/flicker, use a shutter speed that's a whole multiple of the mains frequency:
| Mains | Flicker-safe speeds | Tip |
|---|---|---|
| 50 Hz (EU) | 1/50, 1/100 s | At 25 fps use 180°; at 24 fps use 172.8° |
| 60 Hz (US/JP) | 1/60, 1/120 s | At 30 fps use 180°; at 24 fps use 144° |
What is shutter angle?
It comes from rotary film shutters: a disc with an opening of N degrees spinning once per frame. A 180° opening exposes for half the frame. Digital cameras emulate it; many let you set angle or speed.
Higher fps for slow motion?
Keep the 180° rule for natural blur (e.g. 1/120 s at 60 fps). For sharper slow-mo with less blur, narrow the angle.
The 180° rule and when to break it
The conversions here encode a century of practice. At 24 fps with a 180° shutter you're exposing 1/48 s per frame — the motion blur audiences read as "cinema". Keep the angle and change the frame rate and the shutter speed follows: 1/50 at 25 fps, 1/120 at 60 fps, 1/240 at 120 fps for slow motion that stays crisp when conformed.
The practical trap is lighting flicker. Under 50 Hz mains (Europe), shooting 24 fps at 1/48 can beat against HMIs and cheap LEDs; the standard fixes are 1/50 s — equivalent to a 172.8° angle at 24 fps, which is why that oddly specific number is a menu preset on ARRI and RED bodies — or flicker-free fixtures. Under 60 Hz mains the safe speeds are 1/60 and 1/120.
Creative departures are deliberate: a 45–90° shutter gives the staccato, blur-free action popularized by Saving Private Ryan; 270–360° smears motion for dream sequences or to squeeze exposure out of low light. This converter translates any of those choices between angle and speed for whatever frame rate you're running.
What shutter speed equals a 180° angle?
Half the frame interval: 1/(2×fps). So 1/48 s at 24 fps, 1/50 at 25, 1/60 at 30, 1/120 at 60. That symmetry is the whole convenience of thinking in angles — the motion character stays constant across frame rates.
Why do cameras offer 172.8°?
Because 172.8° at 24 fps equals exactly 1/50 s, which synchronizes with 50 Hz mains lighting and kills flicker when shooting film rates in PAL countries. Its sibling is 144° at 24 fps under 60 Hz (1/60 s).
Does shutter angle affect exposure?
Directly — halving the angle costs one stop. Going from 180° to 90° loses a stop of light; 360° gains one at the price of doubled motion blur. That trade is why low-light shooters flirt with wide angles.