johnnydeep wrote: ↑Sun Dec 04, 2022 4:57 pm
Chris Peterson wrote: ↑Sun Dec 04, 2022 12:30 am
johnnydeep wrote: ↑Sun Dec 04, 2022 12:06 am
I've got nothing seriously wrong with my eyes or brain that I know of (though some friends of mine might disagree). So do you mean if I can keep my finger in focus when it's held 5 or 6 inches in front of me, then, in theory, I should be able to see stereographs such as this? If so, the good news is that I can focus my finger just fine. So, I guess I'll just keep trying to see these stereo images.
Close, but not quite. The amount of crossing is consistent with looking at an object a few inches in front of your eyes. But you're focusing on something that's another foot or so behind that. That's the trick. Normally, your eye position and eye focus are tied together without you needing to think about it. Aim your eyes at something six inches away, and they will focus for a distance of six inches. Here you're aiming for six inches but focusing for eighteen. That is something under voluntary control, but it can take a bit of practice to figure it out.
So, focus on something eighteen inches away but then shift your gaze to this stereogram 6 inches away? PS - I have no problem seeing those "magic eye" images. Are the viewing/focusing methods similar?
The magic eye images work by having your eyes more parallel, not crossing. But otherwise it's the same principle- you're feeding a slightly different image to each eye.
A couple of things to try. From 18 or 20 inches away from the screen, look at the black space between the planet images. Then, slowly cross your eyes, not paying too much attention to what the image is actually doing. You should notice that the images of Mars are doing weird things, maybe becoming three, maybe overlapping in odd ways. But don't shift your focus to them, just play with controlling how your eyes are crossed. When they're at the right amount, there will be a stereo version of Mars, and your brain might do what it's supposed to do and "snap" onto it, the same sort of effect the magic eye images produce.
Another option. Again from 18 or 20 inches back, put your finger right between the two images. Then slowly bring your finger towards your eyes, keeping it in focus. You're looking at your finger, not the image. As you move your finger closer, you should notice the background image splitting into three, and when your finger is around 4-6 inches from your face you should have three equally spaced images. Try moving your finger left and right a little to cover each of them separately (but stay focused on your finger, not the background). Put your finger over the middle one, and then slowly drop it downwards so it's out of the way. Maybe the middle one will snap into focus in full 3D.