|6. 3-D MOVIES: EXPOSURE AND PROJECTION|
The amateur photographer of narrow format movies can produce 3-D movies by making use of the beamsplitter accessories previously mentioned. These must also be placed in front of the projector during projection.
Since a vertical format is not suited for movies, one employs special beamsplitters that produce a wide picture such as the TRI-DELTA stereo attachment, or the ELMO stereo attachment ESM 1.
Both types of stereo attachment have pros and cons. The ELMO is directly constructed for movie cameras with the usual large lens diameters. It is therefore quite large: 24 cm wide; 15 cm high and 6 cm deep. One is supposed to be able to zoom with it to a focal length of 48 mm. Since it creates a large partitioning strip between the single views, relatively much of the picture area is lost. The TRI-DELTA (see fig. 4.10) has a diameter of 40 mm. It creates a narrow partitioning strip between the single views. I do not know whether it has zooming capabilities. This attachment has the disadvantage that it requires the camera to point upwards. It is best to make use of the mirror attachment provided for projection also during exposure so that one can film in the conventional position.
One must, however, be aware that because of the small size of the split format, the required polarizing filters, and the relatively weak light output of the film projectors, a picture width of up to only 80 cm can be expected on the silver screen.
Naturally, talented hobbyists can make 3-D films with two attached Super 8 movie cameras. One must then couple the drive shafts in such a manner that the two apertures open simultaneously. This may also be achieved electronically through a quartz controlled synchronisation device. One can also couple the zoom drives and the distance setting mechanism by using soft, endless belts, such as those used in sewing machines. For close-ups one can also use simple prism attachments as with stereo cameras.
The same holds for the coupled projectors;
the main problem lies with synchronizing the coupling between the film
advance mechanism. As a result, one then has a significantly larger, brighter
Viewing Requirements for Stereo Photographs
Sketched Anaglyph Pictures
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