[Wsummers]

Make a Null at the same 3D position as the camera. Parent everything in the scene that you want scaled up to that null. Now scale the null and everything will appear the same relative to the camera.

I came across this question when trying to use AE’s built in camera tracker which will only allow you to track a scene at its native resolution. If you track a scene at proxy resolution and then want to use the same track with the large resolution files the solution there is to increase comp size to your desired resolution and then multiply the camera zoom by the ratio of the new resolution to the old resolution.