Zeffirelli's use of Light and Windows in Jesus of Nazareth

I have fallen in love anew with Zeffirelli's Jesus of Nazareth over the last week or so as I have watched and re-watched it.  There are so many things to love about the film.  One of them is Olivia Hussey's portrayal of Mary, which is so moving that it is enough to make one want to convert to Catholicism.  Hussey herself was 26 years old when she played Mary and unlike other several other Jesus films, she plays Mary both as the teenage bride and the older, agonized mother grieving at the cross.

The Annunciation is one of the most visually arresting scenes in the film, not only because of Hussey's portrayal of an initially confused but ultimately devoted young woman, but also because of the striking choice not to have an actor playing the angel Gabriel.  Indeed the name "Gabriel" is not even mentioned and the viewer sees Mary as her mother Anna sees her -- it is one half of a conversation in front of light that is pouring in through the window.

Mary awakes at the sound of the window opening, and the light pouring in, and in a point-of-view shot, Mary looks up to see the window:

As she stands before the window, she converses with the angel, but the viewer, like Anna, sees only one half of the conversation:

And ultimately, Mary kneels in obedience to the angel's message in front of the window:

Here is a clip of the scene: