iPhone 18 Pro gives you two separate ways to decide how blurred a background looks. Portrait mode uses software, which Apple lists on its tech specs as next-generation portraits with Focus and Depth Control, while the 48MP Fusion Main camera now has a physical variable aperture that steps between f/1.48, f/1.8, f/2.8 and f/4.0. The short answer: stop the aperture down when you want a scene sharp from front to back or want natural depth in ordinary photos and video, and use Portrait mode when you want a strong, controllable blur with Portrait Lighting effects.
The variable aperture is the headline change on the iPhone 18 Pro camera, but Apple kept every portrait tool it already had, so both approaches now sit in the same Camera app.
| Item | What Apple says |
|---|---|
| Aperture stops | f/1.48, f/1.8, f/2.8, f/4.0 on the 48MP Fusion Main camera, 24 mm (Apple’s tech specs) |
| Mechanism | Six laser-cut blades (Apple’s press release) |
| Apple’s presets | f/1.48 for maximum light, f/1.8 as the default balance, f/2.8 for more depth, f/4.0 for maximum depth |
| Low-light claim | Around 50 percent better low-light performance (Apple’s press release) |
| Portrait tools | Focus and Depth Control, Portrait Lighting with six effects (Apple’s tech specs) |
| Manual aperture | Pro controls in the Camera app: aperture, shutter speed, white balance and a histogram |
What the variable aperture physically changes
A wider opening, such as f/1.48, lets in the most light and gives the shallowest natural depth of field. A narrower one, such as f/4.0, keeps more of the scene in focus. Apple describes f/1.48 as the setting for maximum light, f/1.8 as the default balance, f/2.8 for more depth and f/4.0 for maximum depth when you want a manual effect.
Don’t miss the best of The Mac Observer
Set us as a preferred source and our Apple reporting ranks higher in your Google Search results and Discover feed — one tap, no account changes.
Because the blur comes from the lens rather than a depth map, it applies to everything the main camera captures, including video. Apple’s press release says the camera can also pick a stop itself: f/1.48 in low light, f/1.8 for portraits, or f/4 for group photos.
The 50 percent low-light gain Apple cites comes from that wide opening, and it applies to the main camera only. Apple’s tech specs list the Ultra Wide at a fixed f/2.2 and the 4x Telephoto at f/2.8.
What Portrait mode and Depth Control do instead
Portrait mode builds its blur in software. Apple’s tech specs list next-generation portraits with Focus and Depth Control, plus Portrait Lighting with six effects, and none of that requires the aperture to move.
The Depth setting on Camera Control is the quickest way in. Apple Support describes it as a control to increase or decrease the background depth-of-field effect, and notes that selecting it turns on Portrait mode if it was not already selected.
A software blur is an estimate of distance, while the aperture is an optical fact. Apple has not published how the two interact when both are in play.
Portrait mode vs stopping down
| Portrait mode with Depth Control | Variable aperture | |
|---|---|---|
| Where the blur comes from | Software depth effect | Physical lens opening, six blades |
| Range | Depth slider, Apple has not published f-stop equivalents | f/1.48 to f/4.0 in four stops |
| Lighting effects | Portrait Lighting, six effects | None, it is a lens setting |
| Works in standard video | No, Cinematic mode is the video equivalent | Yes, Apple cites cinematic videos |
| Light gathering | Unchanged | f/1.48 gives the most light |
| How to reach it | Camera Control Depth, or the Portrait mode | Pro controls in Camera, or let the camera choose |
Which to pick, scene by scene
- Group photo: stop down. Apple names f/4 as the setting the camera picks for group photos with greater depth of field.
- Single person, dramatic blur: Portrait mode, for Depth Control and the six Portrait Lighting effects.
- Low light, no tripod: open up to f/1.48, which Apple describes as the maximum-light setting.
- Landscapes and architecture: f/2.8 or f/4.0 for Apple’s “more depth” and “maximum depth” presets.
- Video with a soft background: the aperture, since Apple ties the wide opening to cinematic video, or Cinematic mode for its own focus tracking.
How to reach each control
These steps follow Apple’s published description and may differ slightly once iOS 27 ships on September 14.
- Click Camera Control to open Camera.
- Lightly press Camera Control twice to open the overlay of settings for the current mode.
- Slide your finger to reach Depth, then lightly press to select it. Apple Support says this turns on Portrait mode if it was not already on.
- Slide to adjust the depth effect, then click to take the shot.
- For the aperture instead, open Pro controls in the Camera app. Apple describes it as a customizable experience for aperture, shutter speed, white balance and a histogram, but has not published a step-by-step guide yet.
If Depth does not appear in the overlay, Apple Support notes that not all controls are available in all camera modes, so switch to Photo or Portrait mode first. If you are on an iPhone 17 Pro or earlier, the aperture options will not exist at all.
What Apple has not said
- How Portrait mode behaves when the aperture is set manually to f/2.8 or f/4.0.
- Any f-stop equivalent for the Depth Control slider.
- The exact step list for Pro controls in iOS 27; Apple has described the feature but Apple Support has not published a guide.
Pre-orders for iPhone 18 Pro open on Saturday, September 12 at 5 a.m. PT, with availability on Friday, September 18, at $1,199 for the 256GB iPhone 18 Pro and $1,299 for the iPhone 18 Pro Max according to Apple’s Store page. See our full rundown of the iPhone 18 Pro and how the two sizes compare before you order.
