subject to white background question
The exposure of the background does not change when you move further away from it with your camera. It will only change if you take your background lights further away as well. An oversposed background will look the same from 5 or 20 feet.
When you move further away from a building, the building doesn't get darker in your photos. Same thing with your background. But when you move further away, less light coming from the background will illuminate your subject.
Hope that helps.