Shutter Angle Calculator
Convert the shutter angle of a video camera to an exposure time (shutter speed) and back, for the frame rate you shoot at.
Formulas
- Exposure time (seconds) = (shutter angle ÷ 360) ÷ frame rate (fps)
- Shutter angle = 360 × exposure time (seconds) × frame rate
For example, at 24 fps and 180°, (180 ÷ 360) ÷ 24 = 1/48 second. The calculation uses exact fractions, so there is no floating-point error, and rounding happens only once when the result is shown. A value that divides exactly is shown as an "exact value", and one that does not as a "rounded value (N significant digits)".
What the shutter angle is
The shutter angle says how much of each frame's time is spent exposing, as an angle. At 360° the sensor is exposed for the whole frame time, and at 180° for half of it. The term comes from the rotary shutter of film cameras, a disc with an opening of a certain angle.
- The angle must be greater than 0 and at most 360. An angle above 360° would mean an exposure longer than one frame, so it cannot be entered.
- When you find the angle from an exposure time and the exposure time is longer than one frame, the angle would be above 360°, so it cannot be calculated (the tool shows the reason and the time of one frame).
Frame rates
- The list has 8 frame rates: 23.976, 24, 25, 29.97, 30, 50, 59.94 and 60 fps. 23.976, 29.97 and 59.94 are calculated as exact fractions (24000/1001, 30000/1001 and 60000/1001).
- With "Other" you can enter a decimal (such as 47.95) or a fraction (such as 24000/1001), greater than 0 and at most 1,000.
- A decimal such as 23.976 typed in "Other" is used exactly as typed, so it differs by about one part in a million from the 23.976 fps in the list (24000/1001, about 23.976024). To use the exact NTSC-family value, pick it from the list or type the fraction.
- The frame rate used is shown near the result.
Examples
- 24 fps, 180°: 1/48 second (about 20.83 ms).
- 25 fps, 180°: 1/50 second (20 ms).
- 24 fps, 1/50 second: 172.8° (360 × 24 ÷ 50).
- 30 fps, 90°: 1/120 second.
- 23.976 fps (24000/1001), 180°: 1001/48000 second (about 1/47.95 second).
- 60 fps, 360°: 1/60 second (the same as the time of one frame).
Notes
- The smallest and largest angles and the exposure times you can choose differ between cameras. Some cameras with electronic shutters cannot be set by angle. Check the camera's specifications.
- This is a general relation between angle, exposure time and frame rate; the tool does not rely on a standard from a standards body.
- For exposure changes with ND filters, see the ND Filter Calculator. To convert frames to timecode, use the Timecode Calculator. For the shots of a timelapse, see the Timelapse Calculator.
Frequently asked questions
What shutter speed is 180° at 24 fps?
1/48 second: (180 ÷ 360) ÷ 24 = 1/48.
What angle is 1/50 second?
172.8° at 24 fps, and 180° at 25 fps.
Why can the angle not go above 360°?
An exposure cannot be longer than one frame. 360° is exposing for the whole frame time.
Is typing 23.976 different from the 23.976 fps in the list?
Yes. The one in the list is exactly 24000/1001 fps. A decimal 23.976 typed in "Other" is used exactly as typed, which differs by about one part in a million.