iPhone 18 Pro variable aperture shows small Night mode gains in 9to5Mac test

9to5Mac said it had previously tested the wider aperture's effect on depth of field and found the difference small but definitely present. The publication had intended to test Night mode stills next, but an unmissable night video opportunity took priority. After a ship passed through a bridge, the tester stayed to return to the Night mode still-photo test.

The variable aperture lens offers two complementary advantages for night photography, according to the report: it can increase or reduce shutter speed depending on the effect being sought.

For faster shutter speeds, the widest aperture is boosted from f/1.8 to f/1.48. A wider aperture captures more light over a given period, which should shorten Night mode duration and reduce how long the phone must be held still. Shorter duration lowers the chance that inadvertent movement will spoil the shot.

In tests, 9to5Mac found the difference in duration was rather small, as expected from less than one stop of extra light, but it may be enough to help in some circumstances. In one shot, switching from f/1.8 to f/1.48 reduced the duration from 2.1 seconds to 1.7 seconds. Other test shots showed similar results. The biggest differences are likely in the darkest environments, such as astrophotography, though the tester in London said the city does not get dark enough to see stars, so that could not be tested.

Conversely, there may be times when a slower shutter speed is wanted. Keeping the shutter open longer can smooth choppy water and produce a more pleasing appearance.

By manually reducing the aperture to the maximum of f/4 — a larger number means a smaller aperture — 9to5Mac was able to increase exposure time to 4 seconds. This helped give the water a smoother appearance.

The change helped significantly with reflections on the water, the report said. It cited the reflections of four spotlights on a floating pontoon under the Discover London from the Water sign and compared them with an earlier shot. The smaller aperture also produced a starburst effect from lights, including the pontoon spotlights and a street lamp on the left.

For the ultimate glassy water effect, a significantly longer exposure is needed, according to 9to5Mac. On a standalone camera, the usual exposure for this type of shot is 30 seconds, typically at f/16 or f/22. On an iPhone, that requires a third-party app to combine multiple shots. The report said a 30-second exposure taken from the same place with the Spectre app on an iPhone 16 Pro Max gave the water an ice-like, glassy-smooth appearance. 9to5Mac reviewed the Spectre app in 2024.

9to5Mac concluded that the variable aperture lens is probably not enough reason to upgrade from an iPhone 17 Pro to an iPhone 18 Pro. But for someone considering an upgrade from an older iPhone, the benefits might be enough to tip the balance.