|On the set of "Dead Christmas" with|
a beamsplitter stereo camera rig.
In the case of Cave, Herzog felt that the use of 3D would help the audience to better understand the shape of the cave walls that also played a role 35,000 years ago when the people who painted on the walls used their shape to inform and enhance their paintings. In the case of Pina, the choreography of the dancers and their interaction with the sets and locations are documented with the improved spatial understanding that stereoscopic 3D brings to the filmmaker's toolbox. For the stereo veritas films the stereographer is tasked with calculating and capturing "realistic" stereoscopic 3D that represents the view of the world as if you were there in place of the camera rig.
I believe that our spectrum here deals with the desire and application of truth (veritas) versus story (fabula). I should note that these are not mutually exclusive and that the story (fabula) I refer to here is not the overall narrative of the film itself, but the application of stereoscopic 3D in such a way as to support storytelling choices by the director.
Stereo Veritas < - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - > Stereo Fabula
Cave of Forgotten Dreams TRON: Legacy Avatar
Pina Prometheus Hugo
You'll notice some films are falling toward the middle of this spectrum. These are films that were shot in stereoscopic 3D and are technically good, but seem to lack a sense of 3D awareness. TRON: Legacy was a wonderfully shot movie that used such conservative interaxial separation that the stereoscopic depth is almost nonexistent, the whole movie seems to be at 1% parallax or less, you can almost watch the 3D version without glasses. Prometheus on the other hand had several scenes that were very nicely deep with parallax above 2% or so, but it was inconsistent, as if the stereographer and director did not develop a depth script.
With very few exceptions, Avatar, Hugo, and Coraline all were aware of stereoscopic 3D as a narrative tool and made choices that reinforced the director's vision for the use of depth as well as positive parallax (screen space) and negative parallax (theater space). I need to watch Avatar more closely to really comment on it, but the depth was definitely present and used to give audiences a sense of the wonders of Pandora.
Hugo made extensive use of moving the plane of interest from positive parallax to negative parallax and back again. Scorsese and Demetri Portelli brought the characters out to you when they needed to be close (in both friendly and confrontational ways) and pushed them back when distance was called for.
Selick (Director), Kozachik (DP), and their stereographers Brian Gardner and Nicholas Ilyin made brilliant use of the fact that the strength of the 3D effect can and should be planned and managed in Coraline. Akin to the use of black and white and color in The Wizard of Oz to denote a movement into a new and interesting location, Coraline makes use of shallow 3D at the beginning when Coraline is in the boring real world and changes to deep 3D (along with better weather and more saturated colors) when she first visits the other world.
My thoughts on Stereo Veritas versus Stereo Fabula are that this wonderful tool of stereoscopic 3D should serve the wishes and designs of the filmmakers. 3D is another tool like color and sound that a storyteller uses to enthrall an audience. If some thought is put into that use and a skilled crew (experienced 3D camera operators and stereographers are a must) on hand to produce the story, some wonderful tales can be told.