A few nice demo images I found:
Unreal Engine 4 – Demo
Image by K-putt
4500×6000
Custom settings
r.maxanisotropy 16
r.postprocessaaquality 6
r.ssr.quality 6
r.temporalaasamples 0
r.temporalaasharpness 0-32
toggledebugcamera
Reading at the demo 2
Image by malias
Stop the general strike demo Paris
Unreal Engine 4 – Demo
Image by K-putt
• 30 Megapixel Rendering