After Effects is able to do something like this, and I’ve got After Effects, but I wanted to find out how close I could get, using blender instead.
Some challenges - in AE, it’s easy to just use 3 PNGs with alpha transparency. Unfortunately, using Blender’s defocus node blurs the entire image, regardless of alpha transparency or not. So I had to use the knife tool to cut really close to the edges. Unfortunately, that resulted in the blur only working on that trimmed area, meaning the boy in the foreground is blurry, but his edges are not. I think.
Is there a way to accomplish this better?