Randall is a raging introvert. Detremental if you want to be a journalist. Becoming a photographer seemed the obvious solution. He can stay shielded behind the camera and spend hours in the lab without anybody finding it weird.
Lix is an extrovert. In the middle of the action, surrounded by people, that's where she thrives. She feels lost and alone when there is no one around, which is one of the resaons why she works with a photographer although she can wield a camera.