While it seems that 3D movies are a new technological invention that has only been available to filmmakers in recent years, it has actually been around for a long time. The first patent for a 3D movie process was filed in Great Britain as far back as 1890, and the first movie viewed by a paying audience was shown back in 1922. In the 1950s, 3D movies became popular for awhile, but remained a novelty. In the early 1980s, movie makers again tried to sell the 3D technology, and this time reached more mainstreams producers. Titles such as Jaws 3D and Friday the 13th 3D showed some success. New, computerized cameras and processes led to the latest 3D craze, but these processes did little more than expand on the already-existing way 3D movies are filmed.
Before answering the question on how are 3D movies filmed, it must be noted that not all of today’s three dimensional movies are filmed directly in 3D. Some of them were filmed with standard cameras, and then they are sent to a third-party production company that converts the movies into the third dimension. The three dimensional effects in post-production movies are generally not as good as movies that are originally shot in three dimensions. In many instances, the effect seems forced, subdued, or otherwise unnatural.
The best 3D movies are shot with special cameras that were invented for just that purpose. The most advanced of these cameras is the Sony 3D camera system developed by James Cameron and Vince Pace in conjunction with Sony. Cameron used the cameras to produce two documentaries before using them to film what is considered the greatest 3D movie of all-time, Avatar.
In gaining an understanding of how are 3D movies filmed, it is important to understand how 3D works. Three dimensional vision works on the principle of human binocular vision, the use of two eyes to create one image in the brain. Having two eyes that work together in this way is what allows people to perceive depth. The brain uses the triangulation between each eye and an outside object or point to determine how far away the object is. Because movie screens are flat, all of the images are the same distance away, so a system is used to trick the eyes into seeing two different images.
Older 3D movies were made with two cameras that recorded one image in red and the same image from a different perspective in blue or green. The images were then projected onto the screen using two cameras in synchronization. Viewers had to wear special glasses with red and green or blue tinted lenses so each eye could see only one of the projected images, creating a 3D effect.
Today’s 3D cameras use two lenses to capture two sets of images, but instead of colored filters, the images are differentiated by vertical and horizontal or opposing diagonal polarization. The movies are projected using a standard projector with a special lens that projects the two polarizations used. Viewers still have to wear special glasses, but they are no longer colored. The lenses filter each of the differently-polarized images to each eye, producing the 3D effect.