Motion / Time
Shutter Angle ↔ Shutter Speed + Flicker Safe
Convert between shutter angle and shutter speed at any frame rate, snap to the 180° rule or the nearest flicker-safe speed for 50Hz or 60Hz lighting, live as you type.
Frame Rate & Mode
Reference
Smaller shutter angles (90°, 45°) yield crisp, staccato motion — the look of Saving Private Ryan‘s combat scenes. Larger angles (270°, 360°) create dreamy, smeared motion. 180° is the cinematic default.
Under mains-powered lighting, shutter speeds not aligned to the mains half-cycle can cause visible rolling bands. Use Nearest Flicker-Safe to snap to the closest safe speed for your region.
Results
Nearest Flicker-Safe Shutter Speeds
Shutter Angle, Shutter Speed, and Flicker Safety
Shutter angle and shutter speed describe the same exposure in two different units, and cinematographers move between them constantly. This tool converts either direction at any frame rate, snaps straight to the 180° rule with one click, and finds the nearest flicker-safe shutter speed for your region’s mains frequency — all live as you adjust the fields.
Shutter Angle vs. Shutter Speed
Shutter angle is a film-era concept describing how much of a rotating shutter disc lets light through during each frame — a 180° shutter exposes for half the frame duration, a 90° shutter for one quarter, a 360° shutter for the full duration. Shutter speed is the same exposure expressed directly as a fraction of a second. Because the relationship depends on frame rate, this calculator does the conversion in both directions and shows how far you are from the standard 180° look in stops.
Finding the Nearest Flicker-Safe Speed
Lights powered by AC mains pulse at twice the mains frequency — 100Hz under 50Hz mains, 120Hz under 60Hz mains. A shutter speed that isn’t a multiple of that pulse cycle captures a different point in the brightness curve on every frame, producing visible flicker or rolling bands. Click Nearest Flicker-Safe to snap your current shutter speed to the closest value that stays in sync, or click Set 180° Rule to jump straight to the standard cinematic shutter for your frame rate.
This tool is especially useful for:
- Cinematographers converting between shutter angle and shutter speed across different cameras and frame rates.
- Crews shooting under mixed or unknown lighting who need a quick flicker-safe speed on set.
- Anyone traveling between 50Hz and 60Hz regions who needs to recheck flicker safety for local power.