Kemal is a senior lighting artist and is currently working at Starbreeze Studios
In this tutorial, Kemal goes over how you can use the light source radius values within a light to adjust its softness. This is useful when you want a light to match the shape of its source, such as a fluorescent light, so it looks right on surfaces with a reflective roughness value.
Similar tutorials to this one
Exploring a Mixture of Lights in a Scene in Unreal Engine.