Question 1

Why is shutter angle used in cinema instead of shutter speed?

Accepted Answer

Shutter angle is a legacy term derived from traditional mechanical film cameras, where a rotating disk with a circular opening (the shutter) controlled exposure duration. Because the shutter speed is relative to the frame rate (FPS), shutter angle allows a cinematographer to maintain the same motion blur characteristic even when changing frame rates, ensuring a consistent aesthetic throughout a production.

By using shutter angle, the camera automatically scales the exposure time relative to the frame rate. For instance, a 180-degree shutter angle will always expose for exactly half of each frame duration, regardless of whether the camera is shooting at 24fps or 60fps, providing the standard, natural-looking motion blur preferred in professional cinematography.

Question 2

How do I use this shutter angle calculator?

Accepted Answer

To use this tool, simply input your desired frame rate (FPS) and your chosen shutter angle (e.g., 45, 90, 180, or 360 degrees) into the provided fields. The application will instantly perform the calculation and display the resulting shutter speed in both seconds and fractional notation, allowing you to manually input these values into your camera settings menu.

You can also use the preset buttons to quickly toggle through industry-standard angles. This provides a fast, reliable way to ensure your exposure settings are accurate, especially when switching between different frame rates for slow-motion or standard playback speeds during a shoot.

Question 3

What is the 180-degree shutter rule?

Accepted Answer

The 180-degree shutter rule is a foundational principle in cinematography used to achieve natural-looking motion blur. By setting the shutter angle to 180 degrees, the shutter is open for half of the duration of each frame, effectively doubling the shutter speed relative to the frame rate. This mimics the temporal persistence of vision that human eyes are accustomed to.

Violating this rule can result in unnatural-looking footage. A shutter angle smaller than 180 degrees (like 45 or 90 degrees) will result in choppier, more staccato motion, which is often used for high-intensity action sequences, while a larger angle creates more motion blur, often leading to a dreamlike or softer look.

Question 4

Is my input data saved or stored by this tool?

Accepted Answer

No, this application does not store any of your input data. The tool is designed to run entirely in-memory within your browser session using standard JavaScript variables, meaning no information is sent to a server, saved to local storage, or tracked via cookies.

This architecture is intentionally chosen to comply with strict sandboxed iframe requirements. Because no persistent storage mechanisms like localStorage or IndexedDB are used, your inputs are cleared the moment the browser tab is closed, ensuring full privacy and compatibility with high-security browser environments.

Free Cinema Camera Shutter Angle to Shutter Speed Converter