Oxnard - Port Hueneme Optometry  Dr. Don Steensma 465 W. Channel Islands Blvd, Port Hueneme, CA 93041  805/486-3585

 

3D Movies

As 3D becomes more popular in movies, television, video games and in the workplace, many people will discover that they can't appreciate this new technology because of vision problems.

Years ago 3D films were created with a red filter producing a red image on one of the cameras and a blue filter creating a blue image on the other camera. The two projectors then superimposed the images on the movie screen. Your brain would then combine these two slightly different images to create the illusion of 3D. Unfortunately, this meant that old-fashioned 3D films could not make full use of color.

To get around this problem, modern 3D films use polarized light instead of red and blue light. Normal light is like a wave moving in one direction while vibrating to the side in all 360 degrees. A polarizing filter is like a slit in that it only allows vibration in one direction. A polarized light wave vibrates in only one plane.

Modern 3D movies are projected through 2 cameras with polarizing filters set 90 degrees apart. The glasses you wear when watching a 3D movie use the same polarizing filters to separate out the two images again, giving each eye a slightly different perspective and fooling the brain into seeing 3D.  This is sometimes called passive polarization.  Because one half of the total photons are blocked for each eye the resolution of the screen is lower.

3D TVs use what is called shutter glasses-type technology. Shutter glasses receive signals from the TV, and create the 3D effect by blocking one lens then the other in sync with the TV's refresh rate.  Because the refresh rate functions at between 240 and 480 times per second, it is indiscernible to the naked eye.

An estimated 3-9 million people in the United States have binocular vision problems. If you are not using both eyes together you will not see the 3D effect. If you are using both eyes together but with extra effort you may experience discomfort, dizziness, double vision and headaches.  In these cases spectacles can sometimes be prescribed that allow the eyes to work together better.

I you are having some difficulty with the 3D effect, it is best to pick a seat near the center rear of the studio.  The screen should occupy about one half of your visual field.

 

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