My time has come!
The above stereographic image is for cross-eyed viewing (most stereograms are wall-eyed, so you may need to put your finger in front of your screen until this one comes into focus)
This is an image of Honolulu, Hawaii, published by NASA. Note Diamond Head (the volcanic crater) in the south.
Here are some other stereopairs published by JPL:
Wheeler Ridge, California
Mount Saint Helens
Salt Lake Valley, Utah
Wellington, New Zealand
Not sure why but those NEVER work for me lol
Not this, not magic eye books, absolutely nothing works.
Tried for many hours back in the day
I can only do parallel-view, not crosseyed, those look so surreal that way (inverted height/depth basically)
Is that why I'm seeing things that way? Don't understand the difference really, but is really odd to see Mt St Helens as a sinkhole instead.
Yupp, I never got the hang of cross-eyed viewing, even with the tips that are around, whereas the "looking through the image" technique is super easy for me, basically just relaxing my eyes. I assume there's people where it is the other way around, and the cross-eyed method works better for them.
Basically it's about which image is transferred as information from which of your eyes, and the two different techniques swap the eyes, which also swaps the 3D depth information.
I love the Wellington here viewed the "wrong" way - like the ocean is a massive plateau surrounding the coast, with that strip of developed area rising like another giant wall.
Works opposite for me. Cross-eyed versions look correct, and the parallel/wall versions have inverted depth.
Same thing with magic eye images, they're always inverted, like I'm looking into a mold of what the object is supposed to be.
I tried so long I tried every method, never worked for me. Then eventually I found an image that made it work for me
https://i.redd.it/25c330mmohu51.jpg
(Sorry for the Reddit link). How I do it: put your phone screen right before your nose and unfocus your eyes. Then, don't move your eyes, don't move your focus, but slowly move the phone away from your face. At about 10-20cm distance, you should be able to see a squirrel with a nut in its hands.
After that it became very easy to do other pictures simply by knowing what to expect (an actual 3d image).
That being said the one above is really hard.
If you have astigmatism or greatly different lens prescriptions per eye, it may be very hard for it to work.
If you do have astigmatism, you can kind of 'squeeze' or scrunch your eyelids down to compensate as you cross your eyes, and it may work better without glasses and closer up
Some people it just never works with
Do you happen to have a dominant eye? If you primarily use one eye over the other I dont believe these work. For me, I have a scar in the middle of one eye that prevents most straight ahead vision, so its only used to add peripheral information.