1. Stereography
The Mechanics

2. Mechanics
When creating stereographs there are some key terms to remember in order to make your images better and more believably 3D.
They are:
Parrallax
Homologous points
Focal planes
Accommodation

3. Parallax
This is the shift in parts of the image from one view to the other (left or right views).
Human eyes are next to each other, on a horizontal plane. Therefore, parallax shifts in stereographs should only be to the left or right (along the x axis).
For parallel viewers: shifts LEFT appear closer and shifts RIGHT appear farther away.

4. Homologous Points
These are the parts of the image that stay the same in both the left and right eye views.
A.K.A. Zero Parallax.
Homologous points make it easier to see the 3D image because they allow the user to focus on the image.

5. Focal Planes
Each layer of depth in a stereoscopic image rests on a focal plane. There is a near plane (the closest plane that can be seen in focus) and a far plane (the farthest plane that can be seen in focus).
Most dimensional imagery will exist between these two planes.

6. Accommodation Accommodation makes seeing in 3D easier.
Use overlapping and scale to your advantage.
Use incremental level changes so that the viewer’s eye can follow the depth path.
Difficult
to see in 3D
Easy
to see in 3D

7. Activity Analyze the given stereographic image.
Use a ruler to locate the parallax shifts.
Make notes of your findings around the image (not on the image!)
Considering that shifts to the left are closer and shifts to the left are farther, what order of depth do you expect the images to appear in?
Provide students with color prints of the different stereo pairs. Alternate prints so that when students share with a partner (next step), they won’t have the same image.
Note: Use the left image as the starting point. Measure the right image for differences from the left. Using this standard, left will shift closer and right will shift farther.

8. Image 1
Mark Newbold

9. Image 2
“Stereoscopic Mandala” by Rob Scharein

10. Image 3
“Arcadia” by Ray Zone

11. Activity Continued
Make note of what depth order you predict for your image.
Trade images and notes with a partner.
Use the stereo viewers to test your partner’s conclusions.
Share your findings with your partner.
In this exercise, finding the exact right answer is not the goal. It is an exercise to get students thinking about left and right parallax shifts and homologous points.
After the pair-share, ask students to share their findings with the class.

12. Animated Mandala
View the animated version of the stereoscopic mandala here:
In order to view this in 3D students will need to play it on a computer screen or on their phones, using the 3D viewer glasses.
Inform students that in the next lesson, they will create their own stereographic images.