Aperture, also commonly referred to as "F stops," i an important photography/videography skill to master to achieve depth-of-field. In plain English, aperture is what enables a photography to created a blurred background ("bokeh"). For journalists, aperture enables
This is how to understand manual focus for video. By utilizing manual focus, the "professional look" can be achieved with video. Defocused background, also commonly referred to as "bokeh," is just one of the many advantages of using manual focus for video.