Glad this is useful. I take it you're planning to use the R3? I'm curious how the eclipse will appear in the electronic viewfinder, compared to the optical viewfinder of my 1DXIII. There are incredible nuances in the corona, and a huge dynamic range, that the EVF might not be able to display. You'll get the same photos (if not better) with the R3, but for the personal viewing experience, I'm wondering if it will match the optical view.