Frame rate and shutter speed are separate camera settings that are often confused. Frame rate is the number of images recorded each second, measured in frames per second. Shutter speed is how long each of those images is exposed to light. Frame rate determines how often a movement is sampled; shutter speed determines how sharp the movement looks within each sample.
When to use each
- Raise the frame rate when timing matters, such as identifying foot contact, ball contact, or the frame where a joint reaches its peak angle.
- Use a faster shutter speed when individual frames look smeared, which is common with swings, throws, kicks, and sprinting.
- For slow movements such as a controlled squat, standard frame rates and default exposure are often enough.
- In low light, a fast shutter speed lets less light reach the sensor, so the image may need more light or a higher ISO, which can add noise.
How to see it on video
Pause on a fast part of the movement and step through frame by frame. If the gaps between positions are large, the frame rate may be too low to capture the key moment. If a limb or club appears as a blurred streak, the exposure is too long. Shutter speed cannot exceed the time between frames, so recording at 240 fps limits each exposure to roughly 1/240 of a second or shorter. KineVision Max includes shutter speed and ISO controls in the camera for situations where automatic exposure is not sharp enough.
Common mix-ups
- A high frame rate does not guarantee sharp frames. In dim conditions, automatic exposure may still choose the longest exposure allowed.
- Slow-motion playback comes from recording at a higher frame rate than playback, not from shutter speed.
- Video settings recommended for a smooth cinematic look often include some motion blur, which is the opposite of what frame-by-frame analysis usually needs.
Good analysis footage generally combines a frame rate suited to the movement speed with a shutter speed fast enough to freeze the body parts being measured.