Learning to freeview, Part II

[P3D <PTWW@xxxxxxx>]

(Synopsis available in Part I)

In thinking about what elements were key to finally being successful, I
came up with a few observations.  One was that starting the process
requires first defeating the very natural tendency to look "at" the two
slides in front of your face.  As is often stated, you need to look at
some distant point while setting your focus on the stereo pair.  I
usually hear the advice expressed as: look off in the distance first,
then shift focus to the near object.  Personally I find it easier to
maintain near focus and allow the eyes to diverge.  But how do you force
yourself to do this the first time?  After I got it to work, I realized
what I had done: instead of looking through the slide page at the lamp
centered between the two slides, I looked through the left slide, with
my dominant left eye, at the lamp behind the left slide, and actually
eliminated any conscious perception of the right slide.  And when you
think about it, that is what we do naturally when we look at a distant
scene.  Our dominant eye "looks at" the scene, and the second eye supplies
a sort of supplemental background second perspective to allow our brains
to do the mental gymnastics required to perceive the third dimension.  So
before your next attempt to FV, figure out which eye is dominant, and
concentrate on looking through the corresponding half of the stereo pair
with that eye!

Giddy with my success, I pulled out my copy of "Photographing in 3D" and
tried to FV the stereo prints while sitting on the couch.  After a couple
minutes, I went back to lying on the floor!  Without the see-through
nature of slides, it was harder to "look through" the images, but I was
able to get it to work after a few tries.

I do not have a lot of traditional FV materials at home, so I have not
gotten in a lot of FV practice since my initial success.  One day I did
take out some Realist format slides to FV.  The center-to-center spacing
of Realist format slides is about 2-1/2 inches, compared to 2-1/8 inches
for two 2x2 images in one of my slide storage pages, so it is a little
more difficult.  I later realized that to work up to greater divergence
ability, you can remove the 2x2 pairs from the storage page, hold them
close together, fuse the pairs, and them slowly separate them while
keeping the image fused.  I have only done this once, but want to work
at it some more to get a feel for what my own limits might be.  I do
not have any stereoviews, so I do not yet have any experience trying to
view them.

So what is needed for a FV starter kit?  If you have any 2x2 pairs (try
to stick to ones that were precisely made (slide bar or twinned rig) if
possible) a floor and a lamp, you're in great shape already!  I started
with some of my aerial hypers, most of which have pretty good alignment,
(as nearly as *I* can determine) and moved on to some hand held shoot
and shift pairs.  I think I have an above average tolerance for retinal
rivalry (below average ability to detect alignment errors), so I did not
have any difficulty comfortably viewing the hand held pairs.  Your
experience may differ.

To make the attempt as easy as possible, consider using a binder clip
to hold the slides so you don't have to hold up both arms or worry
about them slipping if you are holding both between a couple fingers
of one hand.  If you have a slide storage page you can put the two
slides next to each other in the page.  However, you can reduce the
center-to-center separation to make the first attempt easier if you
don't use the page, and instead overlap the two slides to bring the
images very close together.

No 2x2 pairs?  If you plan to order anything from Reel 3D in the near
future, ask them to send some samples.  I think they charge about $1
per slide or per pair, I forget which.  (IHNA, etc.) I bought mine when
I bought one of their economy 2x2 viewers.  I'm not sure if you have to
be buying a viewer for them to also sell you a sample pair.  I got two
pairs from them.  One is excellent, the other is not a particularly
pleasing stereo photo.  You could also use your SLR to create some pairs
of your own, of course.

Alternatively, you could use a Realist format slide, but as noted the
spacing is greater.  If you want to start off with closer spacing, and
you have your slides mounted commercially, select one that is a marginal
"keeper", cut it in half, and work with that.  You could also shoot a
few extra slides on your next roll specifically for this purpose.  If
you mount your own slides, you don't have to restrict yourself to using
one of your lesser slides, of course.

None of the above sound appealing?  If there is sufficient interest, I
could create a starter kit with 2x2 pairs and a slide storage page...but
cannot use this forum to tell you about it should I decide to offer it
for sale. ;)

Paul Talbot


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