Please see HERE

Zeiss Stereotar 3D

And HERE

Stitz 3D Stereo SV-1

If people were meant to see 3D movies they would have been born with two eyes. Sam Goldwyn

Stereographs were collected by many middle-class families in the late 19th century. People acquired stereographs of tourist sites they had visited, as well as exotic locales that they would only experience through the wonder of the stereoscope. Viewing stereographs was a common activity, much like watching television or going to the movies today. Stereoviews were also used as an education tool in classrooms.

All ages were hooked into the technology of the time.

The first effect of looking at a good photograph through the stereoscope is a surprise such as no painting ever produced. The mind feels its way into the very depths of the picture. The scraggy branches of a tree in the foreground run out as if they would scratch our eyes out. The elbow of a figure stands forth so as to make us almost uncomfortable

Then there is such a frightful amount of detail, that we have the same sense of infinite complexity which Nature gives us. A painter shows us masses; the stereoscopic figure spares us nothing.

Quickly the stereo system was also being adopted for erotic images as well as science views.

The Stereo Camera

The stereoscope uses two photos to create the 3D image in your mind. It is not a 3D photo. But as technology developed through the early 20th century, these ideas were adopted by camera manufacturers.

In the 1940s, we saw the first mass produced stereo camera. The camera uses two separate lenses and sensors to capture the same scene from different angles. These simulate human binocular vision and create a three-dimensional image.

The first stereo camera was the Stereo Realist, which hit the market in 1947.

This Kodak Stereo Camera followed this in 1954. And the Russian Sputnik stereo camera in 1955.

Models were used to sell cameras even back then and indeed erotic photography is almost as old as photography itself. Stereoscopic images of nude females were made by photographers like Auguste Belloc and Félix-Jacques Moulin in the 1850s. Erotic images became widely available in the beginning of the 20th century.

Many of the erotic images were a recreation of paintings by the masters.

Remember this was the main form of entertainment in middle class families, no TVs, cinemas, or mobile phones.

Camera Position

The images here particularly the one below show the secret to good stereo photography. You need clear distinct layers separated by distance to get a good effect.

To avoid eyestrain and distortion, each of the two 2D images should be presented to the viewer so that any object at infinite distance is perceived by the eye as being straight ahead, the viewer's eyes being neither crossed nor diverging. When the picture contains no object at infinite distance, such as a horizon or a cloud, the pictures should be spaced correspondingly closer together.

The position of the cameras and the angle to the subject makes a big difference to the 3D effect.

The convergence point determines where the object appears in relation to the image.

Convergence can be adjusted by toeing-in (an inwardly-angled adjustment) of the camera lens or by horizontal image translation (H.I.T) in post-production.

Simultaneously manipulating both the convergence and the interaxial gives control over the depth, and the placement of objects within that 3D space.

Parallax is created by the separation of the left and right images. We can also refer to this as The Depth Budget as it describes the limits for negative parallax (in front of the screen plane) and positive parallax (behind the screen plane). Keeping within the depth budget will ensure that eye strain is kept to a minimum – it‟s all about what‟s comfortable to watch not just for a few minutes but for two to three hours at a time for a movie.

You might be surprised how comparatively small parallax changes are needed to produce Stereo3D. For example, Sky TV in the UK recently prescribed a Depth Budget of 2% positive parallax and 1% negative parallax (measured as a percentage of the width of the frame) for the vast majority of the material with short term impact effects not exceeding 4% and 2.5% respectively.

Once the two parallax images have been taken if they are then placed side by side most people can, with practice and some effort, view stereoscopic image pairs in 3D even without the aid of a stereoscope, but the physiological depth cues resulting from the unnatural combination of eye convergence and focus required will be unlike those experienced when actually viewing the scene in reality especially with negative parallax, making an accurate simulation of the natural viewing experience impossible and tending to cause eye strain and fatigue in the viewer

So we can see now how each scene you create has a maximum amount of usable depth within which to create effective 3D.

When objects are placed too far in front of the screen AND too far behind the screen at the same time (too much depth), the viewer will not be able to fuse the stereo 3D image.

Viewing Stereo Images

Stereocards

Stereocards first appeared in the mid 1800s and are still a great experience. They are usually two pictures mounted side by side on a 3.5 x 7" inch card that create a remarkable feeling of depth and dimension.

The advantages of side-by-side viewers is the lack of diminution of brightness, allowing the presentation of images at very high resolution and in full spectrum colour, simplicity in creation, and little or no additional image processing is required. Under some circumstances, such as when a pair of images is presented for freeviewing, no device or additional optical equipment is needed.

The parallel viewing method uses an image pair with the left-eye image on the left and the right-eye image on the right. The fused three-dimensional image appears larger and more distant than the two actual images, making it possible to convincingly simulate a life-size scene. The viewer attempts to look through the images with the eyes substantially parallel, as if looking at the actual scene.

The principal disadvantage of side-by-side viewers is that large image displays are not practical and resolution is limited by the lesser of the display medium or human eye. This is because as the dimensions of an image are increased, either the viewing apparatus or viewer themselves must move proportionately further away from it in order to view it comfortably. Moving closer to an image in order to see more detail would only be possible with viewing equipment that adjusted to the difference.

Of course 3D TV and cinema does not have two images next to each other. They are superimposed on top of each other and the glasses you have to wear separate the two images.

Converting images between stereo formats

I use StereoPhoto Maker Pro to convert images between formats.

It is available for a PC and now available for a Mac although it is a PC software in a shell to work on the Mac here. It is free software.

You can download a user guide here

Standard IMAX

Some IMAX movies are also polarised images.

Standard IMAX movies are 2D projections from large films shot with a wide view panoramic camera. But some are stereographs and can be viewed with polarised glasses or with active shutter liquid crystal shutters that strobe rapidly in sync with the projection.