What is an Expo Disk? Would you please explain that?

Thanks. Great advice. I hadn't thought of using a gray card.

What program or app would you recommend for post processing?

I'm considering purchasing a Canon 80D and am concerned about critical reviews by photo experts which say that the auto white balance setting is worthless and that I would have to manually set white balance. Is this true?

It seems strange that a prosummer camera in this price range would have that problem.