If you're going to geek out on cinematography, this is the way to do it.
In the first five minutes of this video, there's more wisdom about 4K than than can easily be found on the entire rest of the internet.
What matters far more than spatial resolution are acquisition dynamic range and display contrast (which is driven by black levels much more than brightness).
From there they go on to discuss everything from distibution to lighting to, of course, cameras.
Smart guys, good stuff.