Every iPhone until now has had one fixed aperture on its main camera. The iPhone 18 Pro and Pro Max, on sale since 18 September 2026, are the first that let you change it. Apple calls it the first aperture control on iPhone, and it's the setting most likely to change how your photos look, as long as you know what it's doing.

Here's what aperture is, what each of the four settings is for, and the handful of other camera settings worth changing.

What aperture actually does

The aperture is the opening in the lens that lets light in. On the 18 Pro, six small blades open and close to make it bigger or smaller. It's measured in f-numbers, and the numbers run backwards: a small number like f/1.48 is a wide opening, and a bigger number like f/4 is a narrow one.

It changes two things at once:

• Light. A wide opening lets in more light, which helps in the dark.

• How much is in focus. A wide opening gives you shallow focus: your subject sharp, the background soft. A narrow opening keeps more of the scene sharp from front to back. Photographers call this depth of field.

Until now the iPhone created soft backgrounds mostly with software, in Portrait mode. With a real aperture, more of that look can come from the lens itself.

The four settings, and when to use each

The main (1x) camera has four fixed stops rather than a slider. This is Apple's own guidance on what each is for:

• f/1.48: the widest. For low light, and it helps Night mode work faster. Use it indoors, at dusk and in dim restaurants.

• f/1.8: the default, and the one that suits portraits. Subject sharp, background gently soft.

• f/2.8: more of the scene in focus. Good for a person with a place behind them you still want to read clearly, or a product shot where you want the whole object sharp.

• f/4: the most in focus. For landscapes, street scenes and group photos where the people at the back matter as much as the people at the front.

A simple rule: one subject, open it up; whole scene, close it down.

Two things to know. Aperture only applies to the main camera. The Ultra Wide (0.5x) and Telephoto (4x) have fixed apertures, and the 2x setting is a crop of the main camera. And the narrower settings let in less light, so in dim conditions f/4 means a slower shutter or more noise. If a photo taken at f/4 indoors looks soft or grainy, that's why.

How to set it

By default it's on Auto: the camera chooses the aperture for the light and the scene, and Night mode adjusts it in the dark. That's the right setting for most everyday photos.

When you want to choose, aperture sits with the new Pro controls in Apple's Camera app, alongside shutter speed, white balance and a live histogram, and you can pin these to the top of the screen so they're one tap away. Once you've set the aperture yourself it stays there until you put it back to Auto, so get into the habit of checking before your next shot.

The other settings worth changing

• Grid and level. In iOS 27 these sit in the Camera Controls menu inside the Camera app, so you can switch them on without leaving it. Keep both on: they make straight horizons and clean lines far easier.

• Photographic Styles. The new version adds texture and grain controls. Set a look you like once and your photos come out consistent, and you can still change or remove it afterwards.

• Resolution. The main camera takes 24MP photos by default and can take 48MP. Use 48MP (or ProRAW) when you plan to crop or edit heavily, and 24MP the rest of the time to save space.

• Zoom steps. Use the fixed steps (0.5x, 1x, 2x, 4x and 8x) rather than pinching to somewhere in between. The fixed steps are where image quality holds up.

What's new compared with the 17 Pro

The sensor sizes and the 4x telephoto are the same as last year. What's new is control: the variable aperture (the 17 Pro was fixed at f/1.78), Pro controls in Apple's own Camera app, texture and grain in Styles, and new video features including Apple Log 2. The standard iPhone 18 isn't out yet, and so far Apple has only announced variable aperture for the Pro models.

The setting that matters more than all of these

Aperture is a genuinely useful tool, but it doesn't decide whether a photo is good. Light, framing and timing still do most of the work, and they work the same on any phone. If you want to get better at editing what you shoot, AI for Creators teaches the edit on the phone you already have, iPhone 18 Pro or not. For video, our guide to iPhone camera settings for Reels and video covers the rest.

Based on Apple's iPhone 18 Pro specifications and announcement, September 2026.