180° rule

Luckily, the basics of video and photography are essentially the same, meaning all that time spent learning about focal length, aperture, ISOs, shutter speed, and lighting will come in handy here; you just have to apply it in a different way.

To start, you should know about a few “rules” of filmmaking. Much in the way photography has rules, filmmaking has its own set of rules that can help guide you in making good-looking video. One of the first to know is the 180° shutter rule. This came about due to the way motion picture film and shutters operate. Without getting too technical, the shutter exposes each frame for about half of the time it takes to run the frame through the camera, meaning that when you shoot at 25 fps, the exposure is 1/50 second, at 50 fps the exposure is 1/100 second, and so on.

This shutter design created a “look” to cinema that has a certain amount of blur to create what appears to us as fluid motion. So, in general, it is best to stick to a shutter speed of double your frame rate, or as close to it as you can get, and it may mean that you need a neutral density filter to help cut down on light to do so. Now, feel free to break this rule if you want a crisper image or a rapid-fire staccato effect. A famous example of this was the beach landing scene in Saving Private Ryan, where a higher shutter speed created a more frenetic and hectic feeling for viewers.

Confusingly enough, there is another 180° rule, though this applies to character placement and framing as opposed to your settings. When you have two characters talking to each other, a common occurrence in most films, you never want to cross their eye line. Doing so is jarring for the audience and anything that is distracting will remove the viewer from the story you are trying to tell.

Along with this is yet another “degree” rule, this time 30°. Basically, if you are cutting between two different angles, make sure they are at least 30° apart, otherwise you will create a jump cut that can also be jarring to some viewers. While more of an editing rule, it is important to know when you start filming to make sure you have appropriate coverage of the scene. But enough with the “rules” for now, let’s get into some of the numbers that come with digital filmmaking.

Source: BH Photo+Video