Stereoscopy I

Hey breaux,

A couple years ago, I thought that it would be a fun side project to try to create some 3D images. I thought of the IMAX glasses one gets at a movie theater upon admission to a 3D movie. Could I make something similar at home?

As I quickly learned, yes and no. Creating 3D images at home that could be viewable on my projector using the IMAX glasses from the movie theater was not a possibility. 3D IMAX images are created by two projectors flashing images so quickly that it looks like a single constant image to the eye, and then the plastic polarized lenses in the glasses give each eye a view of the corresponding projected image to create the illusion of a 3D movie.

However, 3D images have existed for over a hundred years, so how did people in the early 20th century view them before IMAX and those glasses with red and blue lenses? They used something called a stereoscope.

Stereoscopic images are images that are taken from two different camera positions about two and a half inches apart (the distance between your eyes). The photos are then printed next to each other and viewed through lenses with a divider so that only your left eye sees the left image and only your right eye sees the right image. Together with the magnifying lenses in the stereoscope, it creates the illusion of a three-dimensional image.

This I thought was a more practical project that I could tackle. First, I had to order the lenses. I ordered two plano lenses (flat on one side and convex on the other) 50mm in diameter with a focal length of 100mm (meaning that an image will be in focus when it’s 100mm away from the lens). Many stereoscopes were large instruments that one would hold up to his face, the image in a clip the optimal distance from the lenses. It made the illusion work, but they were sort of bulky and I knew that if I made my own stereoscope, I’d need to be able to move the images around a bit before I nailed down the right technique for taking stereoscopic photographs.

Instead of a larger device like antique stereoscopes, I busted open Tinkercad and designed a simple rectangle that I would hold in front of my eyes with one hand so that my other hand could move the image (probably on my phone) around until I found the right spot to make the illusion work.

After one or two prototypes, this is what I came up with.

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