Re: how to shift your eyeballs outwards.

[P3D Larry Berlin <lberlin@xxxxxxxxx>]

Hi,

Perhaps I'm a bit unique when it comes to viewing 3D images, but I did some
experiments with stereograms created with a cell size of 4 inches. The
purpose was to determine if the diminishment of distance would enable
parallel viewing from a great distance and possibly make stereogram bill
boards a possibility. I know about geometry and that parallel lines are
equally distant at all points, but since a nickel in front of the eyes can
block out a whole car or building, I thought it worth trying. For me it
worked. I was able to view the image from 20 and 30 feet away with relative
ease. I started with an image that had a 2 inch cell size and enlarged it so
that in addition to the cell size increasing, the relative size of the dots
increased too. The apparent depth of the resulting image was truly
incredible. The smaller version was only 8 to 10 inches deep and the
enlarged one viewed at a distance was very much deeper.

It seems that if you can move your eyes even a small amount beyond perfect
parallel, this trick will work at some distance.

Others have been less successful at seeing this image. I find it interesting
that some printed stereogram books use a very wide parallel viewing cell
size that I find uncomfortable, yet I can see the 4 inch cell size image
easily from a significant distance.

I too can cross eye view large images but find it less than enjoyable
physically. Plus crossed viewing results in such a small version of the
image that I find it irritating. Parallel viewing by it's nature increases
the apparent size of image. I'm never satisfied with cross mounted images
due to these factors. In order to enjoy them I have to switch them to a
parallel arrangement and reduce the size appropriately for parallel viewing.
This results in a more enjoyable viewing experience for me.

For photos and other large images I use either a home built fully adjustable
mirrored device or hand made prismatic lenses (simple and effective). The
lenses were cut from a chunk of plastic and hand polished. The best angle is
between 3 and 5 degrees for viewing stereogram images and would be different
for other stereo pair image mountings.

>I can parallel-view (with some effort) images up to about 3" wide (Holmes
>stereoscope format). Unfortunately, hardly anybody can parallel view images
>much wider than that, no matter how far away they are. For parallel viewing
>images on a TV or computer monitor, that means the images can only take up
>a fraction of the width of the screen, which means they are relatively few
>pixels across (and therefore very poor resolution).
>
>I can cross-view much wider pictures (and so can many people), which makes
>cross-mounting generally more satisfactory (higher resolution images, etc.)
>for images on a computer display or television *that are meant to be viewed
>without the aid of a viewer*. (Especially since users may have different 
>screen sizes. I've come across some parallel-mount stereo views online that 
>seem to assume a 14" or smaller screen.)
>
>Of course if the big cross-mount pictures are there, it doesn't hurt to also
>make some small parallel-mount versions available.
>
>John R
>
Larry Berlin

Email: lberlin@xxxxxxxxx
http://www.sonic.net/~lberlin/


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