Does anyone know of those keychain picture viewers that are really popular at the beach? You would get you photo taken, then it would be an instant, and be put in a keychain viewer for a small fee. Does anyone know what type of camera, film, printer, etc?
Google search led me to the following expired service: http://www.domainvanhorn.com/viewer/
As written in the page information, there is a regular slide film in the contraption, which consists of a matte white screen and a single simple lens. This is a setup comparable of the most simple slide viewers which, for example, can be found here:
Also the image on this website explains the mechanism and placement of parts in the contraption pretty well.
In the case of the keychain, an uploaded digital image is exposedto slide film, which is then developed and permanently fixed in the contraption.
You can still buy them. For example, Radex Inc. sells them in lots of 100 for $60. The half-frame film viewer is the one you have pictured, but they also have a full frame version and some translucent ones that are appropriate for prints instead of slides. I'm sure there are other sources as well. Adorama has them for $0.99 each and Amazon has them at $22.50 per 50.
About your question, the most popular camera used to make the photos for the "Keychain" was the Olympus Pen-E. In Brazil it was a very popular camera. The origin of this camera is Japanese. Please, when was a photo taken in your post?In the USA? I did not know that this type of photography was known in the USA. I wrote a book about it, but it's in Portuguese. Go to: https://issuu.com/elinaldomeira/docs/monoculo_so_se_for_aqui__na_minha_t