A 180° shutter angle gives the natural, film-like motion blur most cinematographers aim for — that is 1/48 s at 24 fps.
About this tool
Shutter Angle to Shutter Speed Converter is a free, in-browser tool that translates a cinematographer's shutter angle into a photographic shutter speed at any frame rate — and back again. Nothing is uploaded — the conversion runs locally as you type.
A rotary cine shutter exposes each frame for a fraction of the frame duration set by its opening angle: shutter speed = angle ÷ (360 × fps), which the tool presents as 1 ÷ x seconds. Inverting it, angle = 360 × fps × shutter speed. At 24 fps a 180° shutter gives 1 ÷ (360 × 24 ÷ 180) = 1/48 s — the classic setting for natural-looking motion blur.
Use it to match a stills shutter speed to a cine look, or to keep motion blur consistent when you change frame rate: hold the angle near 180° and the tool gives you the exposure time to dial in.
Frequently asked questions
What is the 180-degree shutter rule?
A 180° shutter angle exposes each frame for half its duration, producing the motion blur audiences read as natural, film-like movement. At 24 fps that is 1/48 s; at 25 fps, 1/50 s; at 30 fps, 1/60 s.
How is shutter angle converted to shutter speed?
Shutter speed = angle ÷ (360 × frame rate), shown as 1 divided by x seconds. A wider angle (up to 360°) means a longer exposure and more blur; a narrower angle gives a crisper, more staccato look.
Why can the calculated angle exceed 360°?
A physical rotary shutter cannot open past 360°, so a shutter speed slower than one frame duration is not achievable in-camera at that frame rate. The tool still shows the number so you can see you need a faster shutter or lower fps.
Does this leave my browser?
No. It is pure arithmetic computed on your device; nothing is uploaded and it works fully offline.