What Is Parallel Stereo 3D?
To recap, a stereographic image or video actually consists of two images or videos displayed side-by-side: one image or video represents the left eye’s view, and the other is the right eye. A Parallel stereographic image or video means the left view is on the left, and the right view is on the right.
Parallel viewing may be the easiest and most familiar way to experience stereo 3D. It’s very similar to the way you would view those Magic Eye autostereograms you used to see everywhere. The basic principle is to align the left eye with the left image and the right eye with the right, thus your eyes are in “parallel”.
How To View Parallel 3D With The Naked Eye
Recall that when an image or video is taken for each eye, the center of the image is the center of the eye’s view. Therefore in order to view 3D in parallel, each eye must be looking at the center of each side of the image: left eye looking at the center of the left, and right on the center of the right.
We’ll use a picture of Victoria as a guide. You can click to enlarge. Notice the two black dots beneath each picture. First, place yourself directly in the center of the stereographic image. Now move back if needed, until you feel your each of your eyes can comfortably look directly at the center of each side of the image.
Focus your vision on the center of the image. To assist you, look down towards the bottom of the picture where the two black dots are. Focus your attention at the space in between the two dots.
Now relax your focus. You can do this by picturing yourself looking at something behind the screen. Another way to do this is to daydream or let your mind wander – notice how your vision focuses outwards and farther whenever you daydream. You’ll know you’re doing it right when the two dots begin to move closer together in your vision. Keep bringing those two dots together until they become one. If you feel your eyes straining to do this, it means you are sitting too close so move a little farther back.
The two dots will eventually “snap together” and your eyes are locked into parallel vision mode. Look above the now single dot and you’ll also see a 3D picture of Victoria.
Parallel 3D viewing has a very short learning curve so after a few tries, you’ll be able to do this without the aide of any guides such as the black dots. Just remember to face directly in the center of the image and move farther back if needed.
More Parallel Stereo 3D Picture Samples
Because your eyes can only uncross so far, you may find yourself having to stand very far away in order for your eyes to align correctly if the image is very large. This also means the two halves of a stereo 3D image can’t be too wide (for example, a panoramic shot) – forcing your eyes to uncross fairly far.
Because of this, you’ll often be farther away from a stereo 3D image than you normally would be looking at a picture in front of you. This creates a smaller-looking image in your field of view that could feel like you are looking at a 3D miniature of whatever the subject is. The finer details are lost and any immersive qualities of 3D are completely lost.
This is why it is important when presenting stereo 3D images for this type of viewing, unnecessary parts to either side of the main subject, should be trimmed as much as possible. For example, a photograph of a person should be focused on that person and not all that’s going on to the left and ride of him/her. You will see we do this with many of our pictures of people on this website.