AFAIK, they don't film anything in 16:9, unless the new HD video cameras do. Film cameras always do Academy ratio (4:3). The cinematographer's and director's monitors show the intended ratio boundaries so they can correctly frame the shot, then crop it later.
So, TNG was filmed in 4:3, but was cropped down on all sides during editing. The TATV shot above was cropped on top and bottom, but the sides (originally cropped in TNG) we retained.
Please let me know if I'm wrong about this (I often am).