The iPhone 18 Pro can change its aperture on one camera only. Apple’s tech specs list the four stops, f/1.48, f/1.8, f/2.8 and f/4.0, against the 48MP Fusion Main camera at 24 mm, while the 13 mm Ultra Wide stays at f/2.2, the 100 mm Fusion Telephoto stays at f/2.8 and the 18MP front camera stays at f/1.9.
That one line decides how much of your day the feature touches. Every frame shot at 0.5x, 4x or 8x is taken at a fixed aperture, so the choice of stop applies at 1x and at the 2x optical-quality crop that comes off the same lens. Our explainer on the variable aperture covers the mechanism; this piece is about what to point it at.
| Item | What Apple published |
|---|---|
| Camera with variable aperture | 48MP Fusion Main, 24 mm |
| Stops | f/1.48, f/1.8, f/2.8, f/4.0 |
| Mechanism | Six laser-cut blades |
| Fixed apertures | Ultra Wide 13 mm at f/2.2, Telephoto 100 mm at f/2.8, front 18MP at f/1.9 |
| Manual control | Pro controls in the Camera app: aperture, shutter speed, white balance, histogram |
| Low-light claim | Around 50 percent better low-light performance |
Apple has not published a shot list. What follows sets its stated purpose for each stop against basic optics.
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The four stops belong to the 24 mm camera
Apple’s overview page gives each stop a job: f/1.48 for maximum light, f/1.8 as the balanced default, f/2.8 for more depth, and f/4.0 for maximum depth in manual work. Apple’s newsroom release adds that the camera can pick a stop on its own, choosing f/1.48 in low light, f/1.8 for portraits and f/4 for group photos with greater depth of field.
Because the 2x frame is a crop of the same lens, whatever stop the Main is set to is the stop that frame is taken at. Apple does not spell that out.
| Stop | Apple’s stated purpose | Where that points you |
|---|---|---|
| f/1.48 | Maximum light, and the stop the camera picks in low light | Indoor light after dark, one subject, a background you want to fall away |
| f/1.8 | The balanced default, and the stop it picks for portraits | Everyday frames, head and shoulders, anything handheld indoors |
| f/2.8 | More depth of field than the default | Two or three people at different distances, a table of food, an object on a desk |
| f/4.0 | Maximum depth for manual effects, and the stop it picks for groups | Group shots in rows, artwork and documents shot flat, a landscape with close foreground |
f/1.48 is for the dark and the shallow
The widest stop exists to gather light. It is the setting to reach for when the room is lit by lamps, when a subject is moving and you would rather not lean on a long exposure, and when you want the background to go soft behind a single face.
It is also the stop with the least margin for error. The wider the aperture, the thinner the plane that lands sharp, so a subject who leans forward between frames can drift out of it. Smart Focus subject tracking is Apple’s published answer, and no numbers are given for how thin that plane is at any stop.
f/1.8 and f/2.8 are the everyday pair
Treat f/1.8 as the frame you take without thinking. Apple describes it as the balanced setting and the one the camera picks for portraits, so most of your library will be shot there whether you choose it or not.
Step to f/2.8 the moment a second person joins, or the moment the subject has depth to it: a plate with a garnish at the front and a glass behind, a shelf of books, a bike against a wall.
f/4.0 is for depth, groups and flat subjects
The narrowest stop is the one to choose deliberately. Groups arranged in rows are Apple’s own example, and the same logic covers a page, a painting or a menu photographed square on, where you want the corners as crisp as the middle.
The trade is light. A narrower aperture passes less of it, so f/4.0 wants daylight, a window or a steady position. Apple publishes no shutter speed or ISO range for any stop.
When to leave it on automatic
Apple’s design assumes most people never touch the control. The camera adjusts on its own, and the manual stops live in Pro controls, a new customizable Camera app experience that also carries shutter speed, white balance and a histogram.
Choose manually when the automatic pick would fight your intent: a group indoors where the camera may open up for light when you want depth, or a portrait in bright sun where you want the background softer than the scene requires. Against the fixed f/1.78 lens on last year’s phone, covered in our iPhone 18 Pro versus iPhone 17 Pro comparison, that automatic behaviour is already the bigger change.
What Apple has not said
Apple has published no shutter speed, ISO or exposure-time range tied to any of the four stops, and no depth of field figures. It has published no step list for setting the aperture by hand either, because the support guide still describes the previous Camera app. Steps may differ once iOS 27 ships.
Nor has it published intermediate stops. The specs list four values, not a range, so treat these as the full set until Apple says otherwise. The iPhone Duo cameras do not get the feature at all: that phone’s main camera is fixed at f/1.6.
iOS 27 arrives Monday, September 14 as a free update, and the full specification list sits in our iPhone 18 Pro launch coverage. Pre-orders open Saturday, September 12 at 5 a.m. PT, with the phones in stores Friday, September 18.
