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MF Cameras
Stereo Mounting
MF Viewer
Rolleidoscop
Digital Twins
Stereo Help
Stereo Methods
TDC Stereo Vivid
NSA 2004
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Please take a moment to check these sizes before you begin downloading images
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The images are presented in cross-eye
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the Stereoscope applet a try.
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Many of these pages use a Java Stereoscope applet by
Andreas Petersik. It made a Java convert out of me and I highly recommend
it.
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So, how do you make a stereo pair?
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The basic principle is that you need to generate two images of the same
subject with a horizontal displacement of about 63 mm. This horizontal
displacement is called the stereo base. The 63 mm base is
good for subjects no closer than about 6 feet. You can use a larger
stereo base for subjects farther away, and a smaller one for subjects closer,
but 60 to 70 mm is a good place to start.
Single camera methods
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The simplest method is called, by some, the cha-cha.
Face your subject, lean a little bit to the left and snap a picture.
Without rotating, tipping, or tilting the camera, lean a little bit to
the right and take a second frame. That's it. You now have
your left and right images.
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 Another
way to produce stereo pairs from a single camera uses a slide board.
A smooth board with a ledge on the back edge will allow you to slide your
camera left to right without rotating, tipping, or tilting it. It
makes much better images than the cha-cha, but then you have to carry your
slide board. You can use any handy horizontal surface as a slide
board. Table top, porch railing, rock...it just needs to be flat
and have a view of your subject.
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When using either of these two methods, I always work left to right.
That is, I take my left image, then shift and take the right. By
always doing them the same way, I never have to sit and study the resulting
images to figure out which is which.
The previous methods (single camera) have the restriction that they are
suitable only for still lifes. If anything moves between the
time you take the first and the second images, you will have objects in
your final images that flicker and distract your eyes. I was using
a slide board to do stereo pairs of cruise ships at dock. When I
started working on the resulting pairs, I discovered that I hadn't counted
on the sea gulls. In every frame they were somewhere different.
The resulting flickering white specks rendered all of my pairs worthless.
If you want to make stereo pairs of moving subjects, you need something more
than a single camera and single lens.
Twin shutter methods
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Many different dedicated stereo cameras have been made through the years.
They have two sets of lenses, two apertures, and two synchronized shutters.
FED, Sputnik, Realist, Viewmaster are a few of the names that come to mind.
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You can also take two cameras, place them side by side.
To synchronize the two shutters, you can couple them (electronically or
mechanically) or just practice pushing the release buttons simultaneously.
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Not a twin shutter method, but still a way to do non still life pairs,
is the Pentax stereo adapter. It uses four front surface mirrors
and attaches to the front of a regular camera. The resulting images
have both the left and right images on the same frame. This is known
as a half-frame stereo pair.
I have tried using a pair of Canon A5 digital camera to produce pairs.
I have had pretty good results, but since both cameras are doing their
own exposure and white balance, the left and right images sometimes need
some editing before they are acceptable. My tests were done with
non-coupled shutters and were therefore not perfectly synchronized. My current
project is to electrically couple the shutters on the two cameras to
achieve better synchronization.
I would also like to try to find a Pentax adapter (which is no longer
made) and try that. I may try building me own with some front surface
mirrors or prisms. Being able to slap a half-frame adapter on the
front of my Pro70 would be a lot easier than carrying around a pair of
A5s. |
Basic rules of stereo photography
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Your images should have a large depth of field. Images made at f11
work better than images made at f2
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With a stereo base of 63 mm, there should be nothing in the view closer
than 6 feet
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There must be only horizontal displacement between your left and
right images. The camera must not rotate about any axis between
shots.
These three "rules" were lifted from the very excellent book by Fritz
G. Waack. You can learn more about it at:
http://stereoscopy.com/library/waack-contents.html.
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About those slide boards
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is very important that your slide board be level. So important, in
fact, that I bought a pocket level to keep with the slide board.
If your slide board is not level, you will introduce a vertical displacement
between your left and right images when you rotate the final images back to
horizontal.
Another thing I did was make a mark every cm along the ledge on the
board. This allows me to easily vary and note the stereo base of
my pairs. I can do the first pair at 60 mm and then do a second at
80 mm.
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