That's also true but also first image is focused on Frank. Second image is focused on Zoe. The focus on the camera determines who's talking but a common factor they both share is the camera is always on Frank's shoulders.
But if you blur something in front of something else in something, it's because you're focusing on the something else. Sort of like when you're looking outside, at a large grey mushroom, and you can't see things behind your head; you're focusing on the mushroom and not them.