iPhone 18 Pro's f/1.48 Aperture Delivers Subtle Portrait Gains Over f/1.78

Q: Why does Apple's latest flagship still struggle with soft details in low light despite massive hardware upgrades?

Because low-light video is still governed by hard physics, not just better specs. The iPhone 18 Pro’s wider aperture and upgraded processing let the sensor gather more light, but in video the phone cannot use the long exposures that still photos can. It must keep shutter speeds short enough to preserve motion, especially in a moving night scene like the Tower Bridge cruise-liner pass, so each frame still starts with limited light data. That forces Apple into tradeoffs. To keep footage bright and clean, the camera raises gain and applies heavy multi-frame noise reduction and detail smoothing. Those tools reduce grain and make the overall image more watchable, but they also blur very fine textures when viewed closely. This is why the reviewer saw strong overall night footage but softer detail on close inspection. Sensor size also remains a constraint. A wider aperture helps, but a smartphone sensor is still far smaller than the sensors used in larger cameras, so total light capture per frame is limited. Apple’s processing can compensate impressively, yet it cannot fully recreate detail that the sensor never captured. The web material supports that balance: Apple’s variable-aperture main camera, faster Night mode capture and improved video pipeline produce a clear jump over earlier iPhones, but low-light video still trails still photography. In short, the 18 Pro is much better at night, but soft detail remains the cost of squeezing usable video out of very little light.

2 articles · Updated · 9to5Mac · Oct 6

Side-by-side portrait tests found the iPhone 18 Pro’s f/1.48 main camera produces visibly stronger optical background blur than f/1.78, though the improvement is modest rather than dramatic.
The comparison held focal length, framing and subject distance constant, using the phone’s new manual aperture controls to isolate the lens change from computational Portrait mode effects.
Closest background elements showed the clearest separation gains, while blur differences faded with distance and became hard to notice in far-off buildings and scenery.
In practical use, the wider aperture improved subject separation in some marginal portrait scenes and adds to other benefits of the new variable-aperture lens, following earlier tests that also showed better night video.