iPhone 18 Pro Aperture Settings Can Create Sun Stars—Use Them Deliberately

The variable aperture in the iPhone 18 Pro and iPhone 18 Pro Max gives photographers a choice previous iPhones did not offer. It can also turn small, bright lights into conspicuous star-shaped points. Early users and BGR’s own shooting have highlighted the effect, especially around reflections and other hard light sources.

That does not automatically make the camera defective. A sun star is an optical effect produced when a bright point of light passes through a small, bladed aperture. Sometimes it gives a cityscape or sunset a crisp graphic accent. In a portrait, product photo, or night scene, it can become the brightest and most distracting object in the frame.

The useful response is not to avoid the new hardware. It is to choose the aperture for the picture instead of treating the control as a quality slider.

The four settings change more than brightness

Apple’s 48-megapixel Fusion Main camera offers four positions in the built-in Camera app: ƒ/1.48, ƒ/1.8, ƒ/2.8, and ƒ/4.0. Apple says the mechanism uses six blades, and the phone can adjust the opening automatically for lighting and depth of field. Manual aperture, shutter speed, white balance, and a live histogram are also available through Pro controls.

At ƒ/1.48, the opening is widest. It gathers more light, which is valuable indoors and at night, and can reduce the need for a slower shutter speed or higher sensor sensitivity. The tradeoff is shallower optical depth of field. Apple describes ƒ/1.8 as a balance between light gathering and depth for portraits.

Moving to ƒ/2.8 or ƒ/4 narrows the opening. More of a group or scene can remain acceptably sharp, which makes those settings useful for landscapes, architecture, and several people arranged at different distances. Less light reaches the sensor, however, so the camera may compensate with a slower shutter or higher ISO. Narrower openings also make defined sun stars around point lights more likely.

Inspect highlights before taking the shot

When a frame contains the sun, a bare bulb, streetlights, chrome, glass, water, or polished metal, zoom into the preview and look at the highlight edges. If a star pattern pulls attention away from the subject, switch toward ƒ/1.8 or ƒ/1.48 and compare again. You can also change your angle slightly, move the light behind an object, or recompose so the reflection leaves the frame.

Clean the lens cover before blaming the aperture. Fingerprints can spread bright lights into broad smears and halos that look different from the more geometric spikes caused by the aperture. A quick wipe with a clean microfiber cloth removes one variable from the diagnosis.

For a deliberate sun star, reverse the process. Choose ƒ/2.8 or ƒ/4, place a small light source near an edge or let the sun peek around a building, and watch the preview. Keep the phone steady because the narrower setting may lengthen the exposure. The histogram can warn when a large part of the image is clipping, but a tiny specular highlight may still be intentionally bright.

Apple’s app is capable, but not fully manual

The stock Camera app exposes only the four hardware presets, even though Apple provides developers an API for positions across the aperture range. It also offers shutter-speed and white-balance controls but no direct numerical ISO control. That limits a photographer’s ability to lock every part of the exposure triangle while comparing aperture settings.

Halide 3.2 uses the API to select intermediate values from ƒ/1.48 through ƒ/4. Its Aperture Priority mode lets the user choose an f-number while the app selects shutter speed and ISO, and its manual mode exposes ISO as well. That is useful when a preset produces a sun star that is too strong but the next Apple setting changes the scene more than desired.

Video creators have another option. Apple’s free Final Cut Camera 2.4 supports precise aperture adjustment on the iPhone 18 Pro, plus aperture-priority and shutter-priority modes. It also exposes ISO, white balance, focus tools, false color, and clipping indicators. Those controls make it easier to keep exposure consistent across a shot rather than letting the phone silently compensate.

Treat aperture as a creative decision

The iPhone still performs substantial computational processing, and changing aperture will not turn it into a full-size interchangeable-lens camera. The small sensor and fixed 24mm-equivalent Main lens place real limits on background separation and low-light quality. Third-party apps also add complexity and may process images differently from Apple’s default pipeline.

Still, a physical aperture is one of the iPhone 18 Pro’s most practical camera additions because its consequences are visible before capture. Start wide in low light or when an unwanted star appears. Stop down when depth matters or when the star is part of the composition. The effect becomes far less frustrating once it is a decision rather than a surprise.