Changing the shutter speed changes the perception of movement, allowing the photographer to capture movement. Long shutter speeds create a blurred image and short shutter speeds freeze movement.
The image above was shot at f 3.5, ISO 100, 18mm focal length and a shutter speed of 1/250th of a second. As is evident, although the model is moving, there is no “blur” in the movement.
In this second image, the model is spinning in the same way as she was in the first image. The second image was shot at f 22, ISO 100, 18mm focal length and a shutter speed of 4/5th of a second. The movement at this shutter speed as far more evident. Note also, the change in colour resulting from the change in aperture and shutter speed.
The perception of movement also changes depending on whether the movement in perpendicular to the camera or parallel to the camera.
Both these images were shot at f 22, ISO 100, 18mm focal length and a shutter speed of 3/5th of a second. When the movement is perpendicular to the camera (on the left), it is more evident. When the movement is parallel to the camera (on the right), movement is still evident, but the amount is less pronounced. The fabric was quite long and flicked toward the camera, but the lens was unable to capture the movement as efficiently.
The Shutter Speed Contact Sheet shows each shutter speed (with varying apertures as the camera was set to shutter priority).