>>3303154In general 1/500th and above will isolate movement unless it's very, very fast. To properly isolate it you'll also need to pan the camera to follow the subjects movement as you take the photo.
If you want a blurred subject but sharp scene, something around 1/60th is probably correct. Leave the camera still. If you want a blurred scene and semi blurred subject you can use said slower shutter speed but pan the camera with the subject in the method previously described.
