Note: observe the clarity of the scene
There is no focus assist light in any region of space, there are no windows or openings
Only the 5 lamps that look ... in this case use the resource plane emissive material, 1 cm below the ceiling.
The render time increases tone a bit, but worth the wait
then edit the ceiling of the room a little with PS ... I still have not mastered well the intensity of the emissive plane.
Even, you can delete the ceiling, darken, change, edit and overall clarity, still exists.
clarity can be achieved, soft, tenenue or strong, high, as the case and the type of scene
It can be improved but the result is nice
I hope you like