Stereoscopic Photography...the Science of Solid Viewing

Compact Digital Camera

The film cameras are heavy and awkward for 'point and shoot work' or immediate photography. Though once high definition scanned the film pictures are of excellent quality – however it is a cumbersome process. What is needed for such work is a simple pair of digital cameras that can go directly to `jpg' digital images. For my part I use a synchronized and mated pair of Sony DSC –W200 Cyber-Shot® mounted and set up in a frame by 3D Concepts of Carlisle Massachusetts USA.

Of course all digital cameras have an elaborate adjustment `set up' which must be correct before the 'immediate' shot is clicked; this is compounded by having two cameras. If the sun is bright then the vital rear LCD display screen is washed out and cannot be seen when it is most needed. The only workable solution is the black cloth shield from the old plate camera days or to retire into the shade. Digital cameras can have image stabilization turned on for hand holding during immediate action. However for good composition and general convenience a light weight tripod is often useful. Because 3D cameras should be level a spirit level is usually mounted on the flash holder.

The standard aspect ratio for my system is width/height of 1.5 so that when printed out as my standard 178 mm by 127 mm image (7x5 inch), 6 mm is cropped off each side. But with the normal digital aspect ratio of 1.33 the print out must either be height cropped or printed out with thin white bars on each side. Height cropping can be tricky but it is probably preferable as the print is larger.

My home made side by side stereoscope with Jacquard plate picture feeds has not yet, for me, been superseded. My current system (camera + stereoscope) is as shown in the adjoining photograph (Note: the photos have been printed out with white bars).

The side by side stereoscope optics was hard to optimize with the photo change mechanism and get even illumination across the print. The minimum lens focal length that I could design to was 280 mm, too long for correct perspective – parallax relationship. Hence my design experiments digressed to a right over left configuration; theoretically the optics was easier to arrange. Alas theory and practice differed and the optical layout was a nightmare, however I did get down to 220mm focal length. Getting light in was solved by using print transparencies and illuminating from underneath, but any simple print exchange mechanism was ruled out. Thanks to Epsom® ink jet transparencies and a HP Photosmart® printer very good quality transparencies could be made. (Actually HP premium transparency film works almost as well at lesser cost). Ultimately this stereoscope worked very well but had practical limitations. The prototype is shown in the adjoining photograph.

All my designed stereoscopes have lenses which makes them great for my own private viewing. Adjustable lenses could be fitted to accommodate diverse other people but at expense and optical redesign. Alas corrective eye glasses and stereoscope lenses do not marry harmoniously- if necessary you incorporate your eye correction into your personal stereoscope design. Truly stereoscope pictures are critical – any slight diminution of quality causes mental anguish and for people with less than good vision lens stereoscopes maybe awkward to use.

Of course there is the old Holmes viewer from the 19th century with prism lenses. They still make them but often they can be bought in antique shops along with their old photos from the period.  However the prints are small and the parallax to perspective relationship is awry; but they work well enough for some uses. Prismatic glasses are now on the market that enable the viewer to take a pair of prints, even large ones, lay them side by side on a table and view them easily. These are ideal for quick and simple stereoscopic viewing, even with eye glasses. (www.nvp3d.com)

But take heart there is a great commercially product for general and successful public viewing that has no lenses (just keep you own eye glasses on if necessary) and uses big full page prints; the Mirscope® (www.mirscope.com). I own and use one but I have no other connection with the instrument.