Columbidae circa Columbus Circle

HOW TO SEE THIS VIDEO IN 3D

***No Special Glasses are Needed***

ALL forms of stereoscopic (3D) viewing work
by giving each eye its own slightly different view
of a scene, so it is necessary for there to be two
images to produce a 3D effect. The two images,
although very similar, are not identical because
the eyes view any scene from a slightly different
location, a few inches apart, and that is sufficient
to result in what one eye sees to be different from
what the other sees. The two parts get fused together
within the mind, which uses the difference (parallax)
to produce an experience of spatial depth. The
apparatus for producing this 3D video and the method
for viewing it rely on this same natural principle.

To see this video in three dimensions you need
to fuse the left and right images into a single image.
This can be done in different ways.

The "free-viewing" method, requiring no special
glasses or gadget, involves either crossing the
eyes or the eye-"relaxation" technique popularized
by the Magic Eye books. The latter method yields
true 3D when viewing "parallel format" stereo (in
which the image for the left eye is presented on the
left side and the image for the right eye on the right).
This video, "Pigeons in 3D in Central Park, New York
City, June 2001", is in the parallel format. Therefore
the "eye-relaxation" method is the recommended
approach for optimal viewing of this video.

(Nonetheless, it is also worth trying eye-crossing/
eye-convergence, which for many people is easier
than "Magic Eye"/relaxed/divergent viewing, even
though, when applied to parallel format stereo, what
then happens is that your right eye sees what is meant
for your left eye and vice-versa, so that you are actually experiencing what is called pseudoscopic stereo. Pseudoscopic stereo may look strange, as if near
has become far and far near, but some people don't
experience this strangeness, and even if they do
the effect can be interesting.)

Try this:
Hold up a finger of one hand a few inches from
your nose: "the close finger". And at the same
time with your other hand hold up a finger further
from your nose, maybe a foot or at arm's length:
"the far finger". Look first at the close finger, and
be aware of what happens to it when you shift
your attention to the far finger. Suddenly you
will see TWO of the close finger. THAT is what
you need to do when looking at this video, to
produce this form of double-vision, so that with the
resulting four images (the original two, doubled)
you then can adjust your sight to make two of them
overlap/fuse. You will then see three scenes, the
center one in 3D. There is a natural tendency,
once the two parts that you want to overlap
have gotten close to one another, for them to
drift, sort of on their own, to a condition of fusion

Seeing the video in 3D and in focus may take a
little practice. To "lock in" the 3D it can help to begin
with the video PAUSED. (And there are countless
still-photography stereograms online with which
to practice too. All old stereocards are in the
parallel format. ) Basically what you need to do is
to look at the video but with your eyes converging
less than they normally would -- positioned, in
other words, as if you were looking at something
BEHIND your monitor but keeping the lenses of your
eyes focused upon the monitor. This is a separation
of two visual activities, focus and convergence,
that normally are never separated. It may take
some practice, but once you have gotten it you
will see how the experience of watching this
video is quite different from that of non-3D
video. Really, it is no longer "television".
It's something else, a different medium.

Here is someone else's explanation if
the above one is not clear:

http://www.3dexpo.com/parallel.htm (less info)