The point is, it's not difficult at all, and the optics setup to do so is actually much simpler than the computational algorithms needed to do it digitally. To think that an expensive DSLR or complex PGM algorithm is required to do so is silly. People have been shooting narrow DOF pictures for most of the past century.
Now to get smartphones to do it is perhaps harder than running out to the store and getting a camera, but I would characterize this as one of those evolutionary rather than revolutionary improvements.
In terms of digitizing, there's this archaic thing called a scanner, but a lightbox/DSLR rig can do it, but with the rise of full frame/narrow/mirrorless bodies from Fuji and Sony, you might not even need to do that anymore...
Now to get smartphones to do it is perhaps harder than running out to the store and getting a camera, but I would characterize this as one of those evolutionary rather than revolutionary improvements.
In terms of digitizing, there's this archaic thing called a scanner, but a lightbox/DSLR rig can do it, but with the rise of full frame/narrow/mirrorless bodies from Fuji and Sony, you might not even need to do that anymore...