Previs reel from a very talented fella named Chris Olsen, who did some amazing shot in Avengers Age of Ultron.
For those that don’t know the term Previs signifies someone who lays out animation rigs along with setting up camera moves and linking them to the data mined from live action plates. From there the director can change angles and shots before they spend the money to render it to full resolution and quality. From The Third Floor’s website (who worked on shots in the film) it is:
 …an abbreviated term for “previsualizationâ€, the process of visualizing and improving a project before the final endeavor is attempted. Historically, filmmakers relied on storyboards, concept artwork, and physical models to help them plan their visions.
Now you know! Cool stuff!