Frame rate and shutter speed: two different choices

Capture rate: how often you record

At 25 FPS, the camera records 25 frames during one second of action. At 50 FPS, it records 50. The higher rate captures more positions of a moving subject, but does not decide how long the finished clip will play.

Keep this separate from shutter duration, which sets how long each frame collects light. Capture rate, shutter duration and playback each have a different job.

Playback rate: how quickly you show the frames

Take 50 frames recorded over one second. Show them sequentially at 50 FPS and they take one second: real time. Show those same frames at 25 FPS and they take two seconds: half speed.

Playback speed is playback FPS divided by capture FPS. In the experiment, 50 ÷ 50 gives 1× speed and 25 ÷ 50 gives 0.5×.

An editor can also drop frames, create intermediate ones or keep a clip at its original duration. Simply putting a 50 FPS clip on a 25 FPS timeline does not guarantee slow motion. The half-speed example assumes all 50 original frames play sequentially.

Shutter duration: the movement within a frame

At 50 FPS, frames begin every 20 milliseconds. A 1/100-second exposure lasts 10 milliseconds, half the interval. This is a 180-degree shutter angle. At 25 FPS, the same angle corresponds to 1/50 second.

The 180-degree guideline is optional. A shorter exposure reduces both motion blur and collected light. If you change from 25 FPS at 1/50 s to 50 FPS at 1/100 s, each frame receives half the light at the same aperture. Playback speed does not cause that light change.

Choose a supported recording combination

The current Canon lab offers 4K at 25 FPS and Full HD at 25 or 50 FPS in PAL mode. The higher-rate example uses Full HD. The camera’s separate 4K 50 FPS crop mode is outside this lab’s framing model.

Motion Lab uses an animated illustration, not a recording of discrete camera frames or rolling shutter. Use the timing readouts to understand the numbers, then judge movement in an actual clip.

Plan the capture and the finished clip

1. Decide whether the shot should play in real time or slower.
2. Choose a supported resolution and capture rate.
3. Choose shutter duration for the blur and light you want.
4. Set playback deliberately in your editor and check the resulting speed.

Try the bicycle scenario to bring these choices together, including focus and smooth camera movement.