Viewing Stereo Flame Fractals

down

Myth Busted!

It is commonly noised about on websites, wiki-whatevers and in conversations, that viewing stereo pictures by “freeviewing” methods is supposedly difficult. That is largely a MYTH.

Freeviewing means that you are able to see stereo pictures without the aid of mechanical devices, mirrors, adaptive lenses, electronic shutter glasses, prisms, color filters or other technical aids. There is a skill involved but it is easy to learn and even easier to use once learned.

To start with let's examine why some people may have difficulty. Here’s a list of potential problem areas:

If you are blind or your eyes are closed

If you only have one good eye

If you have large differences between each eye’s natural function

If you don’t try!

Reason number 4 is the most frequent reason that eye-healthy people might experience problems seeing a stereoscopic image!

Binocular vision

Binocular vision is something anyone with two healthy eyes since birth has without having to actively develop the ability. There are many cues we use to discern the shape and spatial relationship of things around us. When it comes to capturing those cues in images, stereo-disparity is the most profound depth cue available. Each eye normally sees the world slightly different from the other eye, and when the eyes are provided with corresponding images with the same slight differences, the brain automatically interprets depth information! Voila! What a difference!

Read on for a tutorial on how to access the full dimensionality and rich colors in the cross-eyed stereo pictures on this website. If you’ve never done it before, this is the easiest learning method I’ve found so it’s worth trying.

A word about skills

Any new skill involves a learning curve. If at first you don’t succeed, try again! If you only get it for a few seconds, keep trying because as your eyes learn the ‘trick’ it becomes so easy that you can literally stereo free-view for hours at a time without eye strain or unusual effort.

Eye strain, when it exists, has a cause. If you try too hard at first you might get tired. Avoid becoming eye-tired by trying for a few minutes at a time and if it doesn't seem to work, wait for a few hours before trying again.

Once you know the skill, eye strain can still happen and be caused by stereo images that are not properly aligned. This happens because the mind and the eyes will attempt to compensate for alignment problems. This issue is more common in stereo photography than with computerized renderings of Flame fractals. If the images have been collected/rendered properly, there shouldn’t be any misalignments to worry about. The stereo images on this site have been carefully aligned to avoid eye strain.

Tutorial for Cross-eyed Stereo Free-Viewing

Definition: Cross eyed does NOT mean to stare at your nose! It simply means that the view from each eye crosses somewhere between your eyes and the image pair being observed. Since your view will converge comfortably on a printed page/computer screen during normal reading, this is the simplest and easiest of skills!

Simply stated, your right eye will look at the image on the left. Your left eye will see the image placed on the right. Follow the directions below the image.

Easy Directions!

Cup your hands and hold them against the sides of your face so that you are peering out through a diamond shaped hole in the space between your hands.

Close your right eye and look with your left eye at the right side image. In this case it is labeled “Left eye view.” Adjust the position of your LEFT hand so that it blocks the other picture from being seen.

Now close your left eye and look with your right eye at the “Right eye view” which is the one on the left. Adjust the position of your RIGHT hand so that it blocks a view of the other image.

Now open both eyes and look through the opening between your hands. There is almost no effort at all, and your eyes are correctly gazing in the right direction and will automatically lock onto the image in the stereoscopic mode!

Just relax and let your mind absorb what it is seeing. You should easily become aware of the depth relationships for all the details in the image.

Repeat the process several times if necessary.

back up to the Tutorial image

Down to a Stereo Feature Image!

General Guidelines

In crossed viewing, you want to make sure to be farther back from the image pair you’re looking at instead of being too close. The closer you are, the more your eyes have to cross to obtain the right direction. Thus, the bigger the image pair the farther back you need to be for comfort. There is no limit to the image size! Just back up farther!

It works best when you are directly in front of or perpendicular to the image pair. When you are off-center to one side or the other, perspective makes the apparent size of the images seem different. Your eyes can compensate for some of that but it takes more effort.

If you imagine a line going across your face and through both eyes, that line has to be perfectly lined up with and parallel to a similar line going through the center of both images. If the images are turned slightly off from horizontal, you will need to tilt your head the same way so that your eyes line up with the images, and then you can view them again.

Try viewing the images and back up slowly farther away from the stereo-pair. You will notice the view becomes smaller and at the same time, the depth factors will increase. There will seem to be more distance between details in the front of the image to the details at the back. This is because of perspective geometry.

Advanced

Once you become familiar with the experience, you can remove your cupped hands. You will notice that while the viewing is happening, there are two ghost images, one on each side. If you shift your gaze to them, you drop out of stereo viewing mode. Learn to ignore them, or continue using your cupped hands to block the ‘ghosts’ until it gets easier.

Later you will find that an easy way ‘into’ stereo viewing is to think “stereo viewing” and while looking at the center of an image pair, blink your eyes. When you open them, knowing what to do, they shift into the right direction and almost instantly you are freeviewing. Practice makes it easy.

Feathered Headdress

The older tutorial follows... Did I leave anything out of the information above that you think should be included? If you have any comments, please send me an email using the address at the bottom of the page, or visit my gallery on devART and leave a message. Thanks!

Basics

What is Cross-eyed Viewing?

Cross-eyed viewing is more like reading a book than making faces at your friends! The term derives from the fact that the right eye sees the image positioned on the Left and the left eye sees the picture on the Right. When you read a book both eyes are directed to the text on a page. Your eyes are then crossed for anything that is further away than the book. Thus cross-eyed viewing need never be more difficult physically than normal reading.

The trick is to allow your eye’s accommodation, commonly thought of as -focus-, to shift to more distant objects without changing the direction and center of your gaze. This is something like reading a book while staying aware of your pet chewing on your shoelaces, without taking your eyes off of your book.

Learning

Stereoscopic Basics

Most people have two functional eyes, and this provides binocular vision. Each eye sees a slightly different view of your surroundings. Your mind automatically puts both views together in your mental center of visual awareness and since they both see the same scene, you perceive only one view with an automatic understanding of spatial relationships.

One of the primary clues for depth relationships is the very slight disparity or differences that is caused by varying distances to each detail in the scene, perceived along the plane defined by the position of your eyes, and the fact that each eye sees from a different location at the same time.

If there is a tree in the distance and you hold up your hand and look at your hand, the tree seems to become two trees. Each eye sees the same tree but because they are looking at your hand, the more distant tree is seen twice. If you shift your view to the tree, there is only one tree but now it seems there are two copies of your hand.

The pictures you find here appear to be almost identical twins, but if you compare things closely, you’ll see that some details are shifted closer to or farther away from any vertical reference point such as for example the right vertical edge.

In stereo photography you shift the camera carefully from side to side about the same distance as between your eyes, being careful to keep the camera pointed in exactly the same direction. This duplicates the effect of having two eyes. When you view the resulting images properly, your mind sees the spatial relationships pretty much as they were in the original scene.

The reason you cannot rotate the camera while capturing those pictures is because of perspective, where things further away appear smaller, plus the effect of the camera lens which creates a slight distortion of the view.

This is one area where Apophysis has a tremendous advantage! As long as you leave the -perspective- parameter in the -adjust- panel at 0, there is NO DISTORTION of objects with distance. Because of that situation it is OK, even necessary to rotate the “camera view” in Apophysis to obtain stereo views. (More on that later)
Note that if you add perspective in the program you will introduce distortion to stereo pair images. If you don’t use too much perspective and not too much stereo-disparity or camera rotation, then the errors remain small enough to not cause a problem. So, until you’ve played with it enough to know what the limits are, stick with Zero (0) -perspective-.

How to Learn the Technique of Viewing

Start a comfortable distance from the image pair. Farther away is easier than being too close. I suggest perhaps 4 to 5 feet to start with.

Remember the book-reading example? In this case hold up your thumb at arms length and place the thumb in a direct line-of-sight to the image pair. In the following steps consciously keep your view ON YOUR THUMB.

Slowly move your thumb closer towards your eyes. Stop occasionally and allow your awareness to expand and be aware of the Fractal image pair in the background – without actually looking at the fractal image yet. Since there are two images and you have two eyes, you will be aware of 4 distant images though you may not be able to resolve all 4 of them because of overlapping views.

At some magical point, while still watching your thumb, the distant pair of images, seen kind of ‘double’, will have two of the four merge in the center so that there seems to be only three distant images. This is where it can get tricky because you want to look ‘at’ the distant images but if you do that, you only see the two side by side pictures. Resist the urge to shift your view and keep looking at your thumb. Just be aware of when the distant and still blurry images seem to become three.

Stop moving your thumb closer to your face because you’ve located the precise focal point for the “cross-eyed viewing” technique to work.

This next step takes patience and relaxation. Patience because your mind has to adjust to what might be for you a new experience. You want your eyes to remain fixated in the direction of your thumb while your eyes gradually relax and focus on the distant images. Your thumb will become blurry and the distant images will become more sharply focused, BUT your actual gazing direction should still be centered on your thumb. When this works right you will still see only one thumb even though it becomes blurry.

As you become more aware of the distant images, which should seem to be of three pictures, you want to learn to ignore the two outside images and just let your mind dwell on the central image. As it clarifies you will begin to notice that it seems different. There is now depth visible. Some features are clearly in front of or behind other details. The edges of the picture help your mind hold onto this new state of stereoscopic depth awareness.

Now you can slowly remove your thumb, but don’t change the direction in which you’ve been gazing. Stay relaxed and if things are working, just enjoy the view and begin exploring the new level of detail that is evident.

At first it may seem difficult to lock into the correct viewing mode. The mind is used to fixing the gaze at the distance in which an image or object exists. Stay relaxed and repeat the above steps as many times as necessary to re-enter the right viewing geometry.

To avoid eye-strain, don’t try too hard all in the first effort! Take a break and try again later. If your eyes start to feel tired, put off trying again till the next day. Once this method is learned, it is possible to not experience any eye strain, yet stay gazing at a stereo image for as long as you wish – hours if you wanted. To keep from getting bored change pictures and explore through the stereo galleries.

With Cross-eyed stereo images, the larger the image, the further back you should be away from the image so that you don’t have to cross your eyes any tighter than you would for normal reading. With this principle it is possible to put stereo images on the side of a large building and successfully see it in stereo. Just get far enough back so the point where your gaze crosses is comfortable.

Top

Back