Apple’s iPhone 18 Pro main camera has a physical aperture that moves. Six laser-cut blades open and close behind the 48MP Fusion main lens, and Apple’s tech specs list four marked positions for them: f/1.48, f/1.8, f/2.8 and f/4.0.
Every iPhone camera before this one had a single fixed opening, and the iPhone 17 Pro main camera sat at f/1.78 for every frame it ever shot. Apple’s press release describes the change as bringing aperture control to iPhone for the first time, and it reaches exactly one camera on the phone, the 24 mm main. Our explainer on the new camera system covers what the four stops are for; this piece is about the hardware that produces them.
iPhone 18 Pro variable aperture: key facts
| Item | What Apple publishes |
|---|---|
| Stops | f/1.48, f/1.8, f/2.8, f/4.0 |
| Mechanism | Six laser-cut blades |
| Camera | 48MP Fusion main, 24 mm, optical image stabilization |
| Cameras with fixed apertures | 48MP Ultra Wide 13 mm f/2.2, 48MP Telephoto 100 mm f/2.8, 18MP front f/1.9 |
| Manual control | Aperture and shutter speed in the Camera app’s Pro controls |
| Models | iPhone 18 Pro and iPhone 18 Pro Max, both 8.75 mm deep |
What Apple has published about the mechanism
The blade count is the only hardware detail in the announcement. Six laser-cut blades form the iris, and the specs page adds the four f-numbers next to the 24 mm main camera. That is the extent of it.
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Apple has not published what the blades are made of, what moves them, or how the assembly is driven between positions. It has not said whether the movement is audible, and it has not given a cycle rating for the mechanism.
Four stops that are not evenly spaced
Light passed by a lens scales with the square of the f-number, so the four values Apple lists are not a regular ladder. The figures below are worked out from Apple’s own numbers.
| Aperture | Light vs f/1.48 | Distance from f/1.48 | How Apple’s overview describes it |
|---|---|---|---|
| f/1.48 | 1x | Widest | Maximum light, for low light |
| f/1.8 | About 0.68x | About half a stop | The balanced default |
| f/2.8 | About 0.28x | About 1.8 stops | More depth of field |
| f/4.0 | About 0.14x | About 2.9 stops | Maximum depth, for manual effects |
The whole range covers a little under three stops, and the spacing is deliberately fine at the bright end: f/1.48 to f/1.8 is roughly half a stop, while f/2.8 to f/4.0 is a full one. The textbook full-stop series runs f/1.4, f/2, f/2.8, f/4, so Apple has skipped the f/2 position and put a half step next to the widest setting instead, at the end of the range a phone camera spends most of its life in.
A range and a list are not the same claim
Apple’s press release describes the camera as having variable aperture from f/1.48 to f/4. The tech specs print four values inside brackets. Those are two different statements, because a range implies everything in between and a list of four does not.
Apple has not said whether the blades can hold intermediate positions, or whether Pro controls presents four choices or a continuous slider. Until iOS 27 is on a shipping phone, the four printed numbers are the safe reading, and that matters because the rest of the iPhone 18 Pro spec sheet is unusually precise by comparison.
What the iris has to fit inside
Both models are 8.75 mm deep, and the main camera already carries optical image stabilization, so the moving blades share a lens stack with a moving lens assembly. Apple’s overview page also cites a 2.44-micron quad-pixel design for the 48MP sensor behind them.
What Apple does not publish is the true focal length or the sensor’s physical dimensions. The 24 mm figure is a full-frame equivalent, so the actual diameter of the opening at each stop cannot be worked out from anything Apple has printed. The phone as a whole is rated IP68 to 6 meters for 30 minutes, and Apple has not described what protects the blade assembly itself.
The one number that gives the mechanism context is the chip. The A20 Pro and its dual 16-core Neural Engine handle the processing, and the aperture is the part of this camera that is purely mechanical. On the foldable, by contrast, every iPhone Duo lens has a fixed aperture, with the main camera set at f/1.6.
What Apple has not said
- The blade material, the actuator type, or how the assembly is moved.
- Any durability or cycle-life figure for a part that now moves on a camera people use hundreds of times a week.
- Whether positions between the four listed stops exist.
- Whether aperture can be set independently while recording video, and what the ISO range is at any stop.
- The true focal length and sensor size, which is why no physical aperture diameter appears anywhere in this article.
No reviewer has photographed with this camera, so nothing here describes how the mechanism performs. The same caution applies to comparisons with the fixed f/1.78 iPhone 17 Pro camera, which are spec-sheet comparisons and nothing more.
Pre-orders open at 5 a.m. PT on Saturday, September 12, and the phones reach stores on Friday, September 18. iOS 27, which carries the Pro controls interface for the aperture, arrives free on Monday, September 14.
