Using Portrait Mode on iPhone XR

As per

https://support.apple.com/en-us/HT208118

This seems to indicate that portrait mode requires the dual camera system such as what's on iPhone 7 plus, 8 plus, X, XS, and XS Max.

"True" portrait mode does require a dual camera, as you need one to focus on the subject and a second with a different focus for the background. The alternative is to use a very large aperture (with a narrow focus range, or bokeh). This is how a DSLR does it. But there isn't enough room in a cell phone camera for a very large aperture, so portrait mode is a compromise if there's only one camera. Another approach is to use a high end photo editing app that can defocus parts of the image. Or, the ultimate solution, is to have a lot of cameras like the Light model L16 with 16 cameras: https://light.co/camera

As per

https://support.apple.com/en-us/HT208118

This seems to indicate that portrait mode requires the dual camera system such as what's on iPhone 7 plus, 8 plus, X, XS, and XS Max.