How 3D works

How We See

The fact that our left eye and right eye see objects from different angles is the basis of 3D photography. If you try looking at an object through one eye and then the other, you will notice that it slightly changes position. However, with both eyes open, the two images that each eye observes separately are fused together as one in our brain. It is the fusion of these two images that creates normal binocular (3D) sight and allows our brain to understand depth and distance.

3D Photography

To capture images in 3D two camera lenses are used in place of our eyes, set about 2 ½ inches apart, which is the same distance between your eyes (called the interocular or interaxial distance). The two lenses each capture onto separate pieces of film. To review the image in 3D a stereoscopic viewer is needed. This is made of 2 eye pieces, each one feeds only one of the images to each eye, (the right image to the right eye and the left image to the left eye) tricking your brain into fusing the images into a single 3D image (as it would with normal vision).

3D Cinema

To project a 3D film, two individual images representing the perspective of the left and right eye are simultaneously projected on screen. Without special glasses during the presentation, it will seem like you are seeing double, because in actual fact you are seeing two separate images. Fortunately the 3D glasses correct this problem. Each lens of the 3D glasses has a special filter (either red and cyan as in the old style glasses or the more modern polarized lenses) which blocks out the opposing image, allowing each eye only to see one image. Your brain perceives the fusion of the two separate images as one three-dimensional image.

The IMAX 3D Experience

In IMAX to recreate the 3D effect on screen we project two separate films through the same projector, one for the right eye and one for the left, at the same time. The film is projected through a set of passive linear polarized lenses, which match the lenses in the special glasses that the customers wear. The polarized lenses separate out the images making sure that your right eye only sees the right film and the left eye sees the left film. When this information is passed from your eyes to your brain it fuses them together to create the world's best 3D experience.