How this calculation works
A shutter angle states the fraction of a frame period that is exposed. Convert either direction using the frame rate, then compare exposure duration with an independently entered light-modulation frequency.
Exposure seconds = shutter angle / (360 × frames per second)A worked example
At 24 FPS a 180-degree shutter exposes for 1/48 second, about 20.833 ms. That spans about 2.083 cycles of an entered 100 Hz modulation, not a whole-cycle match.
Good to know
Ideal timing, not a flicker-free guarantee. Modulation frequency is not automatically mains frequency. Rolling shutter, pulse shape, dimming, phase and drift can matter.
Reference: ARRI: electronic and mirror shutter timing (opens in a new tab) ↗
An angle is a fraction of one frame
A full 360-degree model exposes for the entire frame period. A 180-degree setting exposes for half of it. Because frame period changes with FPS, the same angle can correspond to different exposure times.
At 24 FPS, half a frame is 1/48 second. At 50 FPS it is 1/100 second. The angle alone therefore does not fully describe the time over which light is collected.
The timelapse interval capture and storage calculator adds count complete timelapse exposures inside a capture window, check start-to-start spacing and estimate playback duration and image storage.
Choose one input direction
Angle mode uses the angle field to solve exposure. Time mode uses the millisecond field to solve angle. The other field stays as an alternative scenario input and is not averaged or combined with the active one.
Exposure cannot exceed one frame period in this model. The tool rejects that inconsistent time-mode input instead of reporting an angle beyond 360 degrees as a normal camera setting.
Whole light cycles are a timing check only
Multiplying exposure seconds by the entered modulation frequency gives cycles per exposure. A whole-number result describes arithmetic alignment in this ideal timing model.
Actual illumination can have complex pulse shapes, changing frequencies or dimmer behavior. Rolling readout introduces another timing dimension. A whole-cycle message must not be read as a promise that the final footage is free of flicker or bands.
Use the result with the next measurement
The timelapse interval capture and storage calculator checks whether full exposures fit the capture window. A shutter-time conversion alone does not establish a complete interval schedule or available storage.
Ideal timing, not a flicker-free guarantee. Modulation frequency is not automatically mains frequency. Rolling shutter, pulse shape, dimming, phase and drift can matter.
A few questions, answered
Is 180 degrees always 1/50 second?
No, exposure also depends on FPS.
Should I automatically enter twice mains frequency?
No, use the relevant measured or specified light modulation.
Does a whole-cycle match guarantee no flicker?
No, other light and camera timing effects remain.