Camera Parallax

What is Camera Parallax?

Camera Parallax is the relationship between the distance of an object is and the speed that object moves across your vision. The farther the object, the slower it will move across your screen.

Why does Parallax happen?

Parallax happens because our field of view and a camera's field of view are both cones, but the image is registered in 2D. This relationship causes a difference in how distances are represented in that 2D image. A person running across your field of view 10 feet away from you and a person doing the same thing 100 feet away from you will appear to be moving at different speeds, even though they aren't, because the percentage of the field of view they are traveling across is different. The person 10 feet away from might travel 70 degrees of you FOV, but the person 100 feet away from you only traveled 10 degrees of FOV, but both have to represented on a 2D image.

When do you use Parallax?

Camera parallax is an important technique for enhancing the depth or energy of a shot. If you want to create a shaky, high energy shot, you would try to avoid camera parallax as having elements in the background that the audience can focus on might take away energy from the shot. However, if you have a wide shot of an exterior scene and you want to show scale and depth in it, parallax is a great way to do it.

How do you create Parallax? How do you get rid of Parallax?

You can create parallax within a shot through translational movements. whether that's moving the camera through space, or moving elements within the shot through space. Left, right, up, down, in, and out movement of the camera will all create camera parallax.

You can avoid camera parallax by keeping your camera in place within, and rotating instead. This all of the elements on screen to move across the screen at the same speed, regardless of how far away from the camera they are.

You can additionally cheat some of these ideas if you are animating in 2D by scaling elements in the shot and moving them at different speeds to create the illusion of parallax.