Meet The Gaffer goes through a typical set up you might encounter with a two camera shoot scenario that might involve an L shaped angled part of the room with windows in the background.
The windows of course have the sunlight streaming through it throughout the day at different strength levels.
Here we are in a hotel presidential suite with a lot of windows that need to be covered with ND gel. In this set-up, the static camera frames the tighter shot and the slider frames the wider shot.