The iPhone 18 Pro and iPhone 18 Pro Max introduce a new variable aperture on the Main camera, upgrading from a fixed ƒ/1.78 to a four-stop range of ƒ/1.48 to ƒ/4.0. This change delivers roughly 50% better low-light performance and gives photographers optical control over depth of field previously unavailable on iPhone models.

Aperture controls how much light enters the lens and hits the sensor. Insufficient light leads to blurry or grainy images, requiring longer shutter speeds or Night Mode, which can further degrade sharpness. The variable aperture allows the camera to adjust light intake automatically, or users can take manual control.

To use the feature manually in the Camera app, tap the six-dot button in the bottom-right, select Lens Aperture from the control pane, and choose from ƒ/1.48, ƒ/1.8, ƒ/2.8, or ƒ/4.0. Users can revert to automatic adjustment by tapping the Auto button.

Lower f-numbers like ƒ/1.48 produce a shallower depth of field, ideal for portraits, while higher numbers like ƒ/4.0 keep more of the scene in focus, useful for landscapes and group shots.