A motion picture camera used to be a light-sealed box with a strip of film running through it. Was it easy to thread? Did it run quiet? How bright was the viewfinder? Today’s cameras are exponentially more complex. They are literal bundles of separate technologies, each lurching forward at a different rate. To understand today’s cameras, you must understand the parts to understand the whole. This is my third annual overview of digital cinema cameras for Filmmaker, and it is being written in the run-up to NAB 2013 in Las Vegas, the world’s largest trade show devoted to digital video …