With an iPhone XS, XS Max or XR, open a photo taken in portrait mode and press the Edit button. The image may take a second or two to load in full, but once, you'll see a series of lines just below the photo labeled Depth .
Over the preset line should be ] f4.5 . This label describes the aperture where the current photo is set, and is also called a f-stop. The smaller the f-stop, the more blurring will be in the background. Conversely, the greater the f-stop, the less it becomes blurred. IPhone XS and XR can be adjusted from f1.4 to f16.
With the slider you can adjust the depth until you get the look you want. Changes are made in real time so you can adjust back and forth and see its impact immediately. When you're happy with your photo, press Ready .