Have you ever wanted to make a film about someone with an evil twin? Or maybe someone who meets their doppelganger? Perhaps your lead character is having a crazy dream with themselves in it? But what if you don't know two people who look enough alike to pull this off? These are all highly possible, with or without a set of twins available to you.
One trick many people use is called a split screen. It's when you take two different shots and playing them simultaneously to make them appear as if they're one. The two shots are layered and when they're perfectly lined up look like they're just one shot. It's terribly convenient if you're working on a very small budget or only have minimal editing capabilities.
There are a few specific things to take note of when you're working on getting a split screen shot. They're all fairly simple but they hold the power to make or break your shot so keeping track of them is quite important.
The most important thing is to make sure your camera doesn't move. At all. If it moves even in the slightest your pictures won't line up and your split screen shot won't look as good. Be sure to use a tripod or a very steady surface. Be extra careful when cutting at the end of your shot as well. You won't be able to get away with someone jus holding the camera.
Be sure to leave yourself enough room that you can do what you need to without crossing the middle of the shot. If you do that, whatever crosses over will be cut off and you'll see that you've got two halves of different shots, not one whole one. Do not cross the line.
Another thing to be wary of it the lighting. If your two halves are lit differently, because a lighting source changed or a cloud moved over the sun, it will also give you away. Shooting in a controlled environment is the best way to watch that but you can shoot outside as long as you really watch and pay attention to the lighting. Try to avoid shooting any time when there is a lot of changes in lighting occurring naturally.
Just as you have to watch for lighting changes you also have to be aware of movements in things that you might be interacting with. If you flop down on the couch and only half of the cushions move due to you flopping on them then, again, it'll be obvious you've shot a split screen shot when the movement stops at the line in the middle. Watch for things that might move when you interact with them.
Another thing it to make sure you've got your timing right. Once you've gone through and filmed the first half of your split screen, whether it's just you by yourself, or you're working with a whole team of people, make sure your timing is right. If one half of your video reacts too quickly or too slowly then everything will be off form start to finish. If you have enough people, the best way is to have someone reading off the lines or giving the actor cues as to when they should react or speak. Make sure to keep everything on time. Go through your script beforehand and determine which would be easiest to do first and be sure to get plenty of takes of each part.
So, there you go. Those are the basic things to remember and be aware of when you're shooting for a split screen shot. If you manage a successful one or have anything you'd like to add I'd love it if you shared them with me! Happy filming!