Why does the 'energy' field on my lights keep disappearing (2.8 beta)? Noob question:  I notice that sometimes the properties display for my lights has an "Energy" field which can adjust the brightness, and sometimes it doesn't -- even for the same light object.   Have not been able to figure out the conditions which hide/show this field, or why it would ever go away:



Any ideas?
In Eevee, you will use "Energy", in Cycles, you will use what is in the image you placed, or Shader Nodes. So depends on the render engine.