Stereo Realist - Design and Engineering

Design and Engineering

The Realist uses standard 135 film. The unusual proportions of the slides (the image was 5 sprockets wide) became the standard for 3-D slides, and is known as "5P" or "Realist Format". It marked a significant milestone in stereoscopy. The arrangement of images on the film (1L-blank-2L-1R-3L-2R-4L...) seemed arbitrary but allowed for a simple film advance mechanism with little film wastage. A special accessory was available that used the otherwise blank frame near the start of the roll to identify the roll, though the procedure for using it was rather elaborate.

Because camera lenses invert the image and flip it left-to-right, orienting the film strip so that the image's "up" is up, and its "left" is to the left, the left-eye image of the stereo pair is to the viewer's right. (See the photograph above.) Note that in the Realist 45 the film cartridge is loaded on the right side of the camera, causing the images to be upside down relative to the numbers. The standard Realist and Kodak stereo camera have the cartridge on the left side, so the images have the same orientation as the numbers.

The routine for taking a photograph with a Stereo Realist is elaborate, compared to a modern camera. One must lift the lens cover, focus, cock the shutter, and manually set the aperture and shutter speed. The wind release button must be depressed briefly while beginning to wind the film to the next frame. The film winding is then completed so that the camera is ready to shoot another pair of images.

Later-model cameras featured a double exposure button which could be pulled out to make a double exposure but could otherwise be left alone as well as a depth of field scale on the focusing knob. Many also had red marks on f6.3, 1/50 and on 20 feet. This was called the "The Three R's in Outdoor Stereo Photography" and is based on the then standard ASA 10 color slide film. Earlier cameras lacked these features but they could be added.

A drawback of "Stereo Realist" type cameras is that the lenses are at a fixed separation, known as "fixed stereo base", which was slightly more than the average distance between the human eyes.The stereo base was ideal for subjects that were 7 to 20 feet from the camera, which worked well for most pictures but was somewhat lacking for more distant scenic shots. Accessories were available to effectively lengthen the stereo base for scenic shots and reduce it for macro shots, but these were seldom used.