Maybe you know what I mean - they’re the precursor to the ViewMaster. My gramma wants me to find one. I’ve been searching for a while now, and all I’ve been able to find are antiques for WAY too much money and things like this, and I don’t know if they serve the same purpose. Does anyone know if relatively inexpensive reproductions are still made?
Yup. Cheapie plastic ones for as little as $2.00, or a very nice wooden repro antique-style steroscope for $39.95:
I might be missing something but I believe all they are is a couple of lenese like you find in reading eyeglasses.
here’s my theory of what makes a stereoviewer. You can probably see photos in streo using NO equipment except those pretty eyes that god gave you but, to make things a bit better:
The lenses , say About 4 diopters, help you focus (especially if you are old) and give the feeling of distance. The frame etc just serves to hold the photo in place , at a fixed distance from the lens.
So, you can see the stereo effect with NO equipment. If you want something more just get some strong reading glasses. That is all those stereo things are. If you want more, build a frame to hold the photo.
Thanks, Rodd - I think that’s what she wants. I’ll bring it her way tomorrow and see…
And, sailor? You’re probably right, but I’m on a mission from gramma. If you want to email me, I’ll give you her phone number - then you can call her up and tell her that 
In addition to the frame and lenses, they usually also have a separator between the pictures, so one eye isn’t distracted by seeing the other image.
And yes, it is possible to view them without equipment. You just have to uncross your eyes in the same way that you do to see one of those random-dot Magic Eye things. It’s a lot easier with the equipment, of course.
If you acquire the skill called “free viewing”, you don’t need a stereo viewer. There are a couple of sites on the web dedicated to free viewing. For example, see http://www.studio3d.com/pages2/freeview.html – which shows both the parallel and cross-eyed methods. Note, however, that pictures prepared for stereo viewers require you to learn the parallel method.
I can do it effortlessly, but some people find that doing it gives them a headache.