Alex Cornell put together this excellent video outlining what he did to create those incredible images of an Iceberg that had flipped over. People of the internet take note, this video should serve as your template for how to make an awesome BTS/how to video. It has a table of contents and everything!
He primarily used two lenses, Canon EF 16-35mm f/2.8L II USM Ultra Wide Angle Zoom Lens and the new Canon EF 100-400mm f/4.5-5.6L IS II USM Lens. He also discusses his new favorite bag the Lowepro Pro Tactic 450.
Also check out Alex's post about this video on his website Moonbase.