Hello guys,
This is an easy way to use photographs for MR backgrounds:
1. Copy your mr Physical Sky into a material slot
2. Turn on 'Use Custom Background Map' within the mr Physical Sky parameters
3. Plug your image into the empty map slot
4. Go back to your environment dialog and change the physical scale to unitless
5. Change the unitless value to 150000 (the higher the value the brighter the output)
6. Render the scene
Good luck,
Simon Blakeney