Summary

I got into Stereoscopy after stumbling on a Facebook group of enthusiasts who love to create and view 3D images. It all reminded me of a toy I used to have that let me look through a binocular type device to see a set of slides arranged on a disk. The disk was advanced using a lever and each slide (which was in fact, two slides) resolved into a 3D image. There is an article on Wikipedia on the subject here https://en.wikipedia.org/wiki/Stereoscopy

What I discovered is that if you have these two so-called parallel view images side by side, it’s possible to un-focus your eyes such that you can see the 3D without any artificial device (free viewing). This however, takes concentration and is not very comfortable so I thought I would try and make my own viewer.

This design converts an iPhone into a stereo viewer, capable of viewing parallel view stereograms arranged to be precisely separated.
This was designed around an iPhone 15 pro (in a case) and it may not fit other iPhone models or smartphones.
The model is in two main parts, the eyepiece (print two) and the hinged iPhone case.
The hinged case has a magnetic latch and two magnets each of 10mm in diameter and 3mm thick are required. The magnets fit into two holes in the phone enclosure and can then be covered by gluing in the two magnet covers.
Amazon link to magnets: https://amzn.eu/d/dL3aiG7
To make each eyepiece work, you need to glue in a magnifying lens 2cm in diameter. I used chap acrylic lenses from Amazon: https://amzn.eu/d/dqPaRhY

There are loads of stereo images to be found on the Internet and it’s also possible to create your own. An iPhone capable of taking “spatial” images can be used and the image can be converted into the two parallel images using an app such as Spatialify. There is an on-line AI web site called immersityAI which can take any “flat” image and convert it into a range of 3D formats. This web site has a low-res free mode and subscription model for higher res images. To work in this viewer, the two stereo images need to be the correct distance apart. I have included several images that I made using ImmersityAI. I use Microsoft PowerPoint to mess with the images & get them in the right position and then export the slides as JPEG files for viewing.

Supports are needed when printing the eyepiece. I used Prusa organic supports which are easy to remove