In early cinema a lens flared when you hadn’t placed you lighting correctly, and was considered sloppy film-making. Later on when we took our cameras outside we used lens flare as a tool, to show that we were no longer kept in a fabricated studio, but that what you were seeing was real. Here’s a nifty video I found by Vox explaining it.

It’s a great video, so show them some support on their YouTube channel here.