The Arrow Camera mod allows you to follow your arrows as soon as they leave the bow. By holding down the C key before and during the draw of your bow and through its release, the camera will follow the arrow all the way to its destination until you let go of C.
It’s a neat way to see your target as your arrow finds it. Obviously it’s much better for long distance shots but it will work at any distance.
You can also use it to see what’s on the other side of a mountain or wall. It’s a great way to get a sense for what’s lurking out of sight without alerting any unnecessary attention.