CARRIE and the Split Diopter

While I most recently saw discussion around split diopters after Jordan Peele’s Us, Brian De Palma famously uses these shots often. Like all his cinematic language, it’s not just to look pretty, but has a distinctive effect or feeling to convey.

Let’s talk first about focus in general. If you’re sitting in a room, you choose what to focus on: something outside the window, a book you’re reading, or an object at arm’s length. But when you’re watching a film, for the most part you’re not in control of what you can see clearly. One common exception is for big establishing shots, vistas, etc., which show a large landscape in a deep depth of field. You can ‘scan’ the picture and everything you look at is in focus, allowing you to take everything in in whatever order you want, for however long the shot is.

In many other shots, the depth of field is more narrow and specific, so the director chooses where the focus sit. By having a part of the frame in focus at any given time, the eyes are ‘directed’ to where the action is happening or something is to be noticed. In other words, the director tells the audience what is important / what to look at by putting it in focus at any given time. This can be done in a variety of ways.

1. a character moving from in focus to out, as in the beginning of the The Host clip below

2. ‘racking’ focus at :14 – once the nurse calls out, the focus goes to her as she draws attention, and then racks back to our hero, now quite near the camera / audience.

3. Imitating the eye scanning a room
, like the opening shot (and some others) here:


4. Focus can move with the camera
, so while the focus stays at the same approximate depth, the object (and thus, the camera) is moving along, like so:


So other than a big wide shot where we the viewer are in control of what information we’re looking at, usually the director has chosen what we see. Certainly the areas around / behind / in front of the focal point can be pretty, and we can look at them, but it requires effort, and no matter what they won’t be clear . . . 

Which is where a split diopter comes in.

A split diopter (as opposed to a deep depth of field) usually means you’re making the sharply defined area of a screen far deeper than our eyes naturally would. IE something close to the camera/viewer is just as in focus as something far away, giving the viewer more to look at at any given time, more ‘control’ of what information they choose to watch as a scene plays out.

Because ‘seeing something close up and something far away in equally sharp focus’ isn’t something we’re used to, this can add to a feeling of surrealism or fantasy, as well as give a general atmosphere of creepiness or horror, a feeling something is slightly ‘off’ as in US:

In Carrie, it creates atmosphere, but is also used specifically to convey Carrie’s unease at being under a watchful authoritarian eye.

Here she is waiting outside the principal’s office with nobody near her:

but when we switch angles (the split hidden in the green stripe of wall between the two):

the principal’s secretary is clearly in focus, and thus seems much closer to Carrie than we know her to be. Carrie *feels* as though she’s being watched, we get the impression someone is always right over her shoulder even when we know they aren’t literally. The split diopter lets the director put us in Carrie’s shoes without POV shots or any sort of dialogue.

The shot is used for many authority figures, such as Miss Collins keeping an eye on the class (the split visible in the open field):

and Carrie has the same feeling at home with her mother (the split mostly hidden by the beam; it’s easier to hide in darker shots than the sunlit one above):

Even when Carrie’s mother isn’t looking directly at her, she can see Carrie as well as we can. 

In class, the shot tells us Carrie doesn’t need to be able to see everyone to know they’re laughing at her (you can clearly see where the split is camouflaged in Tommy’s hair):

Carrie can’t see Tommy directly, but she knows he’s laughing at her, just as we can look between them and see his amusement at her expense and her pain at the same time.

The cinematic language here accomplishes three things at once, all before you factor in the acting, colours, dialogue, etc:

– by putting characters far from Carrie clearly ‘over her shoulder’ De Palma reminds us Carrie always feels authority figures / God are watching and judging

– by letting us choose to look between Carrie’s scared and unsure looks and the faces of those haranguing her, De Palma puts us into her headspace

– by using a shot which looks unlike how we’re used to seeing the world and movies, De Palma gives us a subconscious sense of unease. 

De Palma sometimes uses a split diopter for other purposes in other films, but Carrie is a perfect example of how the straightforward horror genre can use it to help us understand why a protagonist does what she does . . . and perhaps even sympathise with it.  

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