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Stereo3D 165
Various techniques exist for 3D recording. Each method has its advantages and
disadvantages:
• 3D cameras with two lenses: The advantages are obvious; these cameras produce
3D material without excessive work involved. The disadvantage is that the stereo
base width (lens distance) cannot be changed.
• Two cameras on a special mount: This involves a little more work. Two cameras
are mounted on a special support to record material for the left and the right side
of the 3D image simultaneously; microphone booms for stereo recordings may
also be used for this purpose.
The disadvantage in this case is that the shutter releases have to be pressed at
exactly the same time if there are moving objects in the picture. In case of video,
both movies must be synchronized before being edited.
Advantages: Stereo base width may be changed by adjusting the distance
between the cameras; larger selection of camera models.
• Two photos via the same camera: This technique only allows still images. The
camera is simply used to record two images from different perspectives, and
these are used as the right and left images. For best results, use a tripod.
• Consistently fast camera movement, e. g. along a street: Only a single
conventional camera is required in this case, but the range of applications is very
limited. This is the most cost-effective method for creating 3D videos. Material is
filmed at a speed of circa 6-to 15 km/h. During editing, the edited video object is
duplicated and one of the videos is played back with a time lapse. The movement
direction determines which is the right and left image. 3D photos may also be
created using this method.
Warning, minimum distance!
The position of the object closest to the lens is designated as the minimum point. This
minimum point may not exceed a specific minimum point; this is easy to calculate via
the following formula:
Note: Lens focal point (e. g. 25 mm) x stereo base width (e. g. 65 mm) x 1.5* /1
mm= minimum point (2437.5 mm ~ 2.44 m)
*1.5 is a factor derived from the cut-off appearing when filming through a lens.
**1 mm is the so-called "deviation" or "spatial dimension". This only involves a rough
value in this case.
Examples for 3D cameras:
Panasonic HDC-SDT750 ( base width 12 mm): minimum point is approx. 1.5 m.
Fuji REAL 3D W3 (base width 75 mm): minimum point at approx. 3 m; for long-
distance recordings as much as 8 m.
This so-called minimum point has an important role in other aspects of 3D editing.