from Hacker News

Civil War in 3D: Stereographs from the New-York Historical Society (2015)

by LorenDB on 5/29/25, 3:43 PM with 24 comments

  • by kazinator on 5/29/25, 5:40 PM

    For casual viewing with the unaided eye, you want to present stereograms in cross-your-eyes order not stare-into-distance order.

    Most people are not able to cause their eyes to diverge, so the scale of images in a stare-into-distance stereogram is limited by the interocular distance.

    In cross-eye configuration, larger images can be used.

    (Of course, the use of magnification in stereoscopes relieves the issue, as well as making it easier for the eyes to focus, since the magnified virtual images appear farther away. Viewing stare-into-distance stereograms requires the eyes to believe they are looking far away due to the parallel gaze, while simultaneously focusing near on the images; magnification brings the images farther out.)

  • by ge96 on 5/29/25, 8:08 PM

    For an example that works see this squirrel sorry reddit link

    https://www.reddit.com/media?url=https%3A%2F%2Fpreview.redd....

    crazy but I feel sick now ha, I had a VR headset before and I'd get super sick trying to play FO4, VRChat wasn't bad

  • by ramesh31 on 5/29/25, 4:29 PM

    You can see the effect in these images directly without a device, by simply crossing your eyes and focusing on the third central image that appears, similar to those 3D optical illusion books: https://youtu.be/zBa-bCxsZDk

  • by saddat on 5/29/25, 4:38 PM

  • by bredren on 5/29/25, 8:23 PM

    Would be cool to get these converted into spatial photos for Vision Pro.

  • by JeremyHerrman on 5/29/25, 4:31 PM

    Is it just me or are some of these examples not actually stereo image pairs?

    I'm just crossing my eyes to see the "negative" depth image but some like "McLean’s House" and "Lincoln visits General McClellan at Antietam" don't appear to have any depth changes between them.