Now, this part is more general about setting up Image Based Environment and tweaking camera settings before we proceed to light set up and rendering.
Knowing how lights and cameras are working together in Maxwell is extremely important. Due to Maxwell's natural unbiased approach - everything is treated as a "light value" - which makes a lot of sense once you understand it.
Plus, those general principles will help you take a better pictures on your grandpa's camera :)
So go on and check it out - it's only few minutes.