3D Glasses. How Do They Work Anyway?

My recent piece, describing the difference between polarized and tinted sunglasses inspired me to address 3D glasses, since they also use polarization to work. Yes, you read that right. The same polarizing technology which reduces glare when you’re driving, also allows you to see an extra dimension at the movie theater.

TwoRealDglassesblackening

As you might recall, in my last post on sunglasses, polarized glasses work by having a film sandwiched inside the lens which only allows wavelengths of light to pass through on one plane. 3D movie glasses are using a polarizing film (with no corrective lens around it, and that’s why they are so thin), but their film is doing something quite different. RealD is the most commonly used three dimensional movie projection system. And they use a circular polarizing film. So, in other words, instead of letting light through on a plane, it’s letting it through on a circle. This allows them to “wink” the image constantly between the two eyes, and not cause shear, or blurriness as you move your head around to get your drink, or eat your popcorn.

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ISSUES WITH 3D

In order to keep costs for the 3D glasses at a minimum, theaters use the polarizing film mounted into a frame, with no ophthalmic quality lens holding it in place. This impacts your vision in a couple of significant ways.

  • First, with no lens to keep the film rigid, there can be waviness or lack of crispness to your viewing experience
  • Secondly, the lenses scratch very easily, so not only are viewing through a lens with poor optical quality, but there are scratches in your way as well.
  • Additionally, if you wear corrective glasses yourself, and put the 3D glasses over them, you can have trouble with comfort on your nose, or even looking through the right part of the lens.
  • Lastly, since these lenses are made as inexpensively as possible, they are very hard to keep clean and the fingerprints can create additional blurriness impeding your experience.

There are solutions for most of these issues for a relatively low cost. There are RealD compatible clip-ons and standard glasses available for purchase from your local optician, or even from online retailers (just do your homework here to make sure you’re getting good quality). Of course, as all of you know, I wear glasses almost exclusively and while I absolutely love going to the movies I have not enjoyed 3D experiences for all of the above reasons. Also, the polar film paired with the less bright projection of a 3D film makes everything dim and washed out. But I found a supplier for these 3D clip-ons and they revolutionized my film going experience. The optical clarity is much better, since the lenses are ophthalmic. Also, the tint of the polarizing film is lighter, so the screen is brighter. No scratches means I can see what I’m watching and there is no additional weight on my nose.

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Excellent clarity with 3D clip-ons

TROUBLES WITH 3D?

There is a segment who cannot view a 3D film without terrible headaches and sometimes even nausea. Because the image is flickering at an incredible rate to alternate the images between the two eyes, this flicker can cause serious problems for those susceptible to migraines. Just as there are clip-ons for 3D, there are also 3D for converting your experience to 2D. Essentially it makes sure that both eyes are getting the same single image. I have found these for RealD at Amazon.

What About IMAX?

IMAX uses a completely different technology and I have yet to find solutions for all of these situations for them. But since my favorite movie theatre, where I do my charity work is IMAX 3D I am working diligently to find solutions!

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