The best cue to the apparent depth of any scene comes as a result of our "binocular vision" - the ability to instantly process the two different views our eyes see and fuse them together into a single "solid" image with height, width, and depth. This effect is especially noticeable up to about 100' or so, gradually decreasing in intensity with distance. 

 

The principle behind stereo or "3-D" photography is simply to simulate our normal binocular vision, using two images which correspond to what each eye would normally see.  This typically involves the use of a "stereo" camera, having two identical lenses separated by a distance approximately equal to the distance between your eyes.  Two regular single-lens cameras mounted side-by-side can also be used, by simply activating both shutters at the same time.  And for stationary subjects, one single-lens camera can be used, moved appropriately side-to-side to obtain the two images.  Whatever the method, the resulting right and left pictures, when viewed so that each eye sees only its particular image, seem to fuse into one view having all the depth of the original scene.  This technique is unsurpassed for creating images with maximum realism and impact. 

 

Stereo images have been around for over 150 years.  The most popular commercially produced formats have been the stereoview cards, lenticular prints, 3-D movies, and the View-Master reels.  In addition, amateur stereographers have made millions of their own 3-D images, especially since the introduction of the Stereo Realist system in 1947.

 

The good news is that all these formats (and more) are still available to stereographers today, and thousands of people around the country and the world are actively engaged in producing 3-D images.  Whether you take pictures for the sake of sharing special places or events with others, to express yourself artistically, or for any other reason, a stereo image will nearly always do a better job of achieving your goal than a “flat” 2-dimensional image will.

 

Because stereo images can be made in so many formats, one of the first steps in taking stereo pictures is deciding what you want the finished product to be.  For our purposes here, we will concentrate only on "still image" formats and equipment, leaving other formats such as film, video, computer-generated 3-D and holography for another time.

 

 

Stereo Print Systems

In the print format, the most common type traditionally has been stereoview cards, which have separate left and right images mounted side-by-side.  These are typically viewed through a stereoscope, which has two lenses in a small covered housing, and a wire frame on a wooden bar in front of the lenses to hold the card.  Focusing is accomplished by sliding the card frame towards (or away from) the viewing lenses.  The most common size for stereoviews is 3-1/2" by 7";  however, both larger and smaller cards have been produced.  Commercially produced mounting cards are available, and some view makers produce their own custom-made cards as well.  Images for these cards can usually be made using any type of camera; however, the old “Sputnik” and the new “3D World” medium-format stereo cameras are particularly well-suited for making stereoviews, due to their use of 120 roll film which produces large 2-1/4" negatives.  Stereoviews have become a popular stereo format now that computer-based imaging has made it easy to do.

View-Magic Print Viewing System

Another way to view stereo print pairs is with a device called the "View-Magic" print viewer.  This inexpensive viewer uses four mirrors to allow viewing of stereo print pairs mounted vertically, one above the other, instead of side-by-side.  The advantage of this system is that stereo prints of nearly any width (including panoramic prints) can be very easily viewed in 3-D.  Though the View-Magic viewers are no longer in production, similar viewers are available.

 

Lenticular Stereo Prints  

A different stereo print format which has long been popular is the "lenticular" 3-D image.  These pictures use a special printing process where extremely thin slices of the images are aligned vertically behind a clear, finely-ridged lenticular material.  This material acts as a lens to direct the slices of the right and left images to the appropriate eye.  A special 3- or 4-lens camera (such as the Nimslo, Nishika, ImageTech 3-D Wizard, 3-D Magic, and others) is usually required to produce the original images, and the film must be sent to special labs for processing.  The advantage of this format is that it allows you to easily view these images without special glasses or viewers.

 

Argus Print Viewing System  

For simplicity and convenience, this system is hard to beat.  The Argus stereo camera (also found under the “Loreo” and Discovery” labels) uses a special mirror arrangement inside the camera and an angled film path to take 3-D pictures that require no special processing or mounting.  Just load in a roll of 400 ASA film, decide whether you want to use the built-in flash, and shoot away.  There are no settings to adjust, and any subject from 2-1/2' to infinity will be in focus.  Because the images are compatible with standard print processing equipment, prints can be quickly and inexpensively made, and immediately viewed with the included viewer.  For many people, this is an ideal way to begin making their own 3-D prints.

 

 

Stereo Slide Systems

The vast majority of stereo photography since 1947 has been done in the Stereo Realist format, or a modified version of this format.  This system uses standard 35mm transparency film in dual-lens cameras, and takes left and right images that are nearly square in shape.   These images are then mounted in a 1-5/8" by 4" mount for viewing or projection.  Over a quarter-million of these cameras were manufactured in the 50's and 60's, and many of them are still in use today.  The most commonly available models are the Stereo Realist, the Kodak Stereo, the Revere 33 Stereo, and the TDC Stereo, though dozens of other cameras of this type can be found as well.

 

Standard "Realist" pictures are about 5 "sprockets" wide (compared to the standard 8-sprocket image taken by most modern cameras), and most stereo mounting, viewing, and projection equipment has been designed for images of this size.  A few stereo cameras have been made which produce wider (7-sprocket) images, and superb stereo pictures can also be made using regular single-lens cameras either alone (for stationary subjects) or "twinned".  

 

 

Once your slides have been mounted, you have the option of viewing them either in a hand-held viewer or on a silver screen, using a stereo projector.  There are many stereo hand viewers available, ranging in price from a few dollars to well over $100.  Most have adjustable focusing and a built-in light source;  some also have glass lenses and have an interocular (eye spacing) adjustment.  The Realist ST-61 "red button" viewer is the most popular, but there are dozens of different models available.

   

There also are many stereo projectors to choose from, most of them costing from $200 to $450. 

The most common models are the TDC 116, the TDC 716, and the Compco Triad.  Some newer projectors are also available, but at much higher prices.  A pair of Kodak Ektagraphic III projectors can also be used for slides in standard 2” x 2” mounts, needing only the addition of polarizers in the light path.  With any of these projectors you must use a silver screen (not white), and special polarized glasses.

 

View-Master System  

Known around the world for the millions of commercially-produced reels, the View-Master system is also a format for the amateur stereographer, though it is not as popular as the other systems already mentioned.  Two cameras in particular - the View-Master Personal and the View-Master Mark II - were manufactured for the purpose of making your own personal reels.  Both cameras use standard 35mm film.  Blank reels and insertion tools are available (though not always easy to find), but a special film punch is required which is fairly expensive (currently around $300).  If you do not take enough pictures to justify the purchase of a punch, one alternative is to send your film to a mounting service and have this done for you.  View-Master reels can be used in any of the View-Master viewers, or projected using the View-Master Stereomatic 500 projector.  Again, a silver screen and polarized glasses are required when projecting these reels in stereo.

 

 

 

Taking Stereo Pictures

As you begin taking stereo pictures, you will find there are some differences in the way you approach stereography compared to regular planar photography.  For example, you will want to compose your pictures to take advantage of the depth you are now able to show.  One rule of thumb is that a good stereo image will contain at least three planes of depth; fore-ground, middle-ground, and back-ground (the more planes, the better). For best results, keep the range of depth in your scene approximately within the range of depth available for a lens aperture of f 8, even though you may be actually using a different aperture size.   

 

Another difference is in the way you adjust your focus, aperture, and shutter speed settings.  In stereo photography you will usually want to obtain the maximum depth-of-field possible, since pictures that are sharp from front to back help to maintain the realism of the scene.  As a result, your lens openings (f-stop settings) will tend to be higher (f 5.6 to f 11), and your shutter speeds a little lower (1/100 sec. or so);  the exact settings depending of course on the amount of light available and the sensitivity of the film you use.  It is usually best to select films with a minimum of "grain" to help reinforce the realism of the picture. 

 

This larger depth-of-field makes the exact setting less critical;  however, it is a good idea to take advantage of the "hyperfocal" markings on the camera to obtain the maximum sharpness over the widest possible range.  These markings are typically on the side of the lens or on the focusing dial, and show the range of distances which will be in focus for a particular focus setting at different

f-stops.  For example, if you set your focus at the hyperfocal distance of 20' at an aperture of f 8, everything between 10' and infinity will be in focus.  If the most distant part of your image is only 20' away - say, for an indoor picture - setting the focus at 10' (again at f 8) will give you a sharp image from 6'8" out to 20'.  These distances can also be obtained from depth-of-field or hyperfocal tables.  Using this information can help you to maximize the sharpness and realism of your 3-D pictures.