Stereoscopic Photography...the Science of Solid Viewing

Why Take Stereoscopic Pictures

Why take Stereoscopic Pictures? The cameras are awkward and clumsy, the viewers are even more awkward and the processing is expensive. Why bother when we all have small simple digital cameras that are the acme of ease to use?

The answer is very simple! Because they are much better; they contain far more visual information. This is a 3D world; all living creatures live in three dimensions. Axiomatic!

Ten years ago that axiom prompted a question in my mind: how to do it? This is how I answered that axiom and question.

Our brains compose a 3D image of the world around us in our minds. It is normally a dynamic image because we are constantly moving our heads and eyes. Take a moment to experiment with and reflect upon your own vision. The optical information used is two flat 2D images from which we learn (very early) perspective, parallax, colour and focus. We learn it dynamically by moving our heads but also statically with our heads and scenes still. In addition we learn to create within our minds error correction algorithms so that the corrected mental picture is accurate and very high definition. Actually we see two (left and right) very wide angle pictures but gaze only on a very small portion of the pair at any given moment; the wide angle picture is vaguely held in mental background.

With still stereoscopic photograph we have no dynamic components or focus distance information; only fixed perspective and parallax. Consider this: gaze at a scene, do not let your eyes lock-on to any object; fix the two mental pictures (left and right) in your brain as a composite 3D picture. Duck your head away and substitute in that position a stereoscopic camera. Click - you will have two physical pictures equivalent to the components of the mental picture in your brain. Now insert the two physical pictures into a stereoscope and view them as a composite 3D picture. The mental and physical 3D composites should match. You may gaze around and concentrate upon any portion of either 3D image. The only thing missing in the stereoscope image will be the focus distance information; with the stereoscope it is always `distance'.

The above precept is all that is needed to conceive a complete stereoscopic system. Arrangement of the camera pair, design of the matching stereoscopes and projection system. Indeed that precept was all that I had some ten years ago when I need a new hobby. The only stereoscopic thing that I had to experiment with was a 100 year old antique. Not really much to work with; but proof that the concept could be made to work easily.

I experimented with left and right pictures taken by a single camera mounted on a simple traverse. These picture pairs were then viewed in my antique prism stereoscope. The perspective was wrong, the parallax was wrong and the viewing angle was wrong. What I had was a toy. Time for analysis - just how does our vision work? What is the geometry of perspective and parallax - how can they be approximately modeled mathematically? What are the engineering compromises that must be made to optimize the design of a stereoscopic system? The result of my deliberations has become a complete amateur system, cameras, stereoscopes and screen projection that approaches realistic photography.

No it is not perfect, nor is it nearly the world's best system! It contains many compromises, some distasteful. But it works very well in practice and it is easy to enact plus being reasonably inexpensive.

As for me well! This is not a personal qualification résumé - as a long retired electronic technologist I do not write such résumés any more. Suffice to say that I am a technologist and not an artist when it comes to photography. Need I say more? You either take the scheme expressed here or - you do not!

People have asked me for a list of the equipment that I use. So I shall oblige them with such a list. This is not to be taken as an endorsement of these products, but simply a statement that I use them. None of it was expensive though some of it should soon acquire antique value.

Brian McConnell 

Cameras	Old Pentax ME 35 mm film cameras, Pentax M 28 mm lenses and Pentax M 50 mm lenses as an option (rarely used). Cameras are 30 mm wide for nesting
	Single Zoom lens 28-80 mm. For use on single Pentax mounted on a traverse
	Old Contax 139 35 mm film cameras, Zeiss Distagon 28 mm lenses used for distance and scenery shots. Cameras are 38 mm wide for nesting
	Olympus 8080 digital camera for experimental work and close up shots with traverse.
Film	For negative film Fuji or Kodak 200 ISO  5x7 inch prints For positive film Fuji Provia 100 ISO  Plastic mounts. ( Agfa is no more) With the best processing that I can get.
Projectors	Old Kodak 4000 series with Schneider curved field 150 mm lenses and Prinz polarizing filters. Bright lamps.
Screen	Back projection. Screen-Tech ST-Professional W 1.2 m x 0.8 m ( German) Front projection Da-Lite  silver screen for stereoscopic
Polarization	Simple linear Quardature. Requires very careful set up to reduce cross image trouble. Some day I shall convert to circular as an experiment
Polarized glasses	Rainbow Symphony ( California USA ). Though there are numerous other suppliers
First Surface mirrors	Not available from my supplier any more. Try the optical supplies for amateur telescope making.
Lenses of stereoscopes	Aspheric eye glass lenses. Your friendly neighbourhood optician.
Stereoscope Frame	Home work shop and local cabinet maker.
Camera mounts	Camera pair mount and traverse for single camera. Home work shop.
Slide Viewer	Twin Elite 2x2 viewer Berezin Stereo Photography.