… for Visual Effects

Tip #694: What is Parallax?

Larry Jordan – LarryJordan.com

Reducing parallax is important in panoramic stills, VFX and Stereo 3D video.

Parallax is the difference in the apparent position of an object viewed along two different lines of sight; say from the left eye to the right eye, or each lens of a stereo 3D video camera.

As the eyes of humans and other animals are in different positions on the head, they present different views simultaneously. This is the basis of stereopsis, the process by which the brain exploits the parallax due to the different views from the eye to gain depth perception and estimate distances to objects.

In addition to its use in making stereo3D believable, parallax is also used in panoramic images, visual effects and web design.

EXTRA CREDIT

Even if your camera setup is perfectly level, you won’t be happy with the results for panoramic images until you eliminate image parallax. Image parallax occurs when near and far objects don’t align in overlapping images. For example, if you’re shooting a scene that contains a fence line, each fencepost in Image 1 should line up with its twin in Image 2. You can eliminate the effects of parallax by placing the optical center of the lens (not the camera) directly over the point of rotation.

Learn more here