I have been interested in Stereoscopic Photography (3D stereo pairs) since the early 1980s. I started by making slides with a 35 mm camera. I took two pictures in succession, moving to the right or left between pictures while trying to stay focused on a single point. To view the 3D images, I intially used a hand viewer, but quickly progressed to using two slide projectors with polarized lenses, a silver screen, and polarized glasses. I also purchased two simple 35 mm cameras, mounted them on a single bar, then used a dual remote shutter release to take both pictures at the same time.
This worked for a number of years until it became impractical to continue making slides; Kodachrome was discontinued in 2009 and processesing ended in 2010. Instead I reverted to the single camera method and taking two pictures in succession. Only now I use a digital camera or a smart phone. Photo editing software lets me "fix" the images for rotation and offsets. Eventually I plan to purchase two inexpensive digital cameras and rig a common shutter for them. That project will likely have to wait awhile.
A stereo pair has one image for the left eye and one for the right eye. The goal is to have each eye only see its appropriate image. There are special viewers on the market to make this easy, but with practice you can force your eyes to do it without an aid. I just relax my eyes until the image doubles. With the doubled images, the goal is to make the right side of the left image overlap the left side of the right image. When this happens, it will look like you have 3 images in a row and the center one will appear in 3D. Good Luck!
The 3D effect is most lifelike if the two images are from vantage points separated by the distance between your eyes. If the images are taken with a greater separation, then the 3D effect is magnified and the objects look smaller than you would expect. I routinely do this for pictures of landscapes.
One of the hazards of taking pictues in succession is that things (people, cars, animals, etc.) move between the two images. This results in a noticable artifact in the 3D image. Another challenge is focusing on the same object between the two images. These hazards can be avoided by using a two-camera setup or by using a special image splitting lens.
For more information on stereoscopic photograhy see stereoscopy.com
I inserted the stereo pairs in Adobe Acrobat files to ensure the width of each image is 2.5 inches (5 inches for the pair). The center of the two images are roughly 2.5 inches apart which is also roughly the distance between your eyes. This assists in enabling your brain to fuse the two images for the 3D effect.
Below are relatively recent sets of stereo pairs. I hope to add more as I find the time to scan the older slides and pictures. Hope you enjoy them.
Doerry Home in 2001
Pentagon Damage on September 15, 2001
Thomas Edison National Historical Park on July 16, 2011
Hoover Dam, Bryce Natioanl Park, and Cedar Breaks National Monument in June 2016