On the iPhone 8 Plus, bokeh took on a dull appearance, with softer edges and a uniform shape across the frame. The effect was pleasing yet unconvincing. (To be clear, Portrait mode has always performed a blur effect much more complex than a simple gaussian blur since the beginning, contrary to popular belief.) The iPhone 13 Pro comes out swinging with bright and sharp bokeh, even distorting its shape near the frame’s edges in a realistic manner. Simulating bokeh in this complex manner on a smartphone, nearly in real-time, is incomprehensible to me. Once iOS 16’s public beta was unleashed upon my device, the new foreground blur left me floored. Portrait mode finally runs what I’d consider a full simulation of photographic depth of field, where it felt incomplete before.
Portrait Mode has come a long way since its first iterations. The earliest photos from my iPhone X look more like a simplistic separation of a foreground object and a blurrier background; Portrait photos taken on my iPhone 12 are far more convincing, to the point where I use Portrait Mode more often than I ever used to. My eyes may be screwing with me, but it even appears to handle the glow from backlit elements in a natural way.
That said, I still have not found Portrait Lighting very useful. It does not seem to have benefitted nearly as much from the significant investments in Portrait Mode.