I love this. Charlie Sorrel, with examples of the Focos photo app:
The universal iOS app lets you edit the focus of your Portrait mode photos in crazy depth (pun intended).
How does it work?
Focos 2 uses machine learning to calculate the depth of any photo, and then apply portrait-style blur to it. That means you can take portrait photos on the iPad and, wildest of all, you can apply a portrait background blur to photos you’ve saved from the internet.