Speaking of Johnnie Manzari, he wrote a post yesterday marking the 10 year anniversary of Portrait Mode:
Initially, Portrait mode was seen as a giant math problem. You’d do disparity calculations on the two sensors and output a depth map. The problem was this approach feels and looks digital; it feels fake. In areas without texture, it’s impossible to do this calculation. In areas with ultra fine detail, a lower resolution depth map leads to terrible transitions and a full resolution depth map takes forever to compute. One solution would be to reduce the amount of bokeh so the issues are not as obvious. But then you lose the whole point of the feature, which was to make it look like you had a large, wide-open lens.
The solution to this conundrum — the tradeoff between artifacts and the amount of blur — was quite elegant, but it took a while to stumble across. There’s a saying in painting that if you get the eyes right, nothing else matters. Inspired by this principle from oil painting, the idea was to make sure we never got the eyes wrong.
I remember getting the call to test out portrait mode before its release. The marriage of history, art and computational science that came together to make this possible is still incredible to me to this day.