Vector for Camera Direction I know that one can use a Gradient texture and Texture Coordinates node to fade an object out the farther it is away it is along an axis. They can even use a Mapping or Separate XYZ node to change the direction of the fade.

However

Using a Mapping node can be tedious, especially in an animation. I was wondering if it was possible to fade an object out away from the camera direction via a straight up Vector/Input node output or a combination of Vector/Input nodes.
You could use camera distance instead, that way it dynamically adjusts transparency relative to camera position dynamically.

Just use the Input > Camera Data node instead. Some math nodes to adjst the factor may be needed.