As you watch the Hannibal finale, you may notice that Hannibal is typically filmed in two ways: with his profile or with half his face in shadow. It’s subtle, but it reinforces our knowledge that he is not who he would have everyone believe.
The moment Will figures him out, though, we see Hannibal’s entire face illuminated. We see what Will sees, the stark truth, fully realized. We no longer see the juxtaposition between light and dark in Hannibal’s face; we see everything, and Will sees everything.