Looking for real 3D shooting experience? Holographic 3D is real 3D. Whether you are looking to maximise comfortable viewing depth (not 6-10% depth budget BUT 95-100% depth budget). Contact Felix to find out how your existing Stereoscopic 3D content can be enhanced and future proofed to meet the demanding standards of Holographic 3D display systems that will be in the market around the end of 2012. Want to know more about shooting to accommodate ‘look around’ 3D viewing with Holographic 3D? Contact Felix to find out how its done.
It really is the future. I could stop here but its easy for most readers to discuss this. However, I have seen and experienced the prototype showing full depth 3D (not the shallow 3D experienced with Stereoscopic 3D) and better still, no depth cue mismatch so no headaches at all... want to no more? Read the article here.
More on this? You can download the article on my brochure page here, or see below.....
How will H3D impact shooting style?
Having spent a considerable amount of time with H3D and its creators it has gradually dawned on me that with such an incredible display technology, the prospects are that we will have to ‘finesse’ our shooting styles to really make the most of it.
One of the most dramatic changes H3D brings about is the functionality, which allows several users watching the same set to focus on different scene points – concurrently! The easiest way to imagine this is to think of the difference between viewing a film versus being at the theatre.
With the viewer having total control over what they actually focus on is one thing but the subtlety of H3D is that when each viewer picks their point of focus in the scene, the rest of the scene naturally blurs much the same as it does in the real world. Change your scene point, it is in focus and everything else is blurred. With this in mind, shooting the most practical and usable content to exploit H3D is likely to mean shooting at hyperfocal distance.
Keeping in mind that H3D is totally compatible with 2D and more importantly with Stereoscopic 3D, there will always be traditionally shot content that will ‘adhere’ to our long established principles of cinematography. However, there will be an opportunity for a ‘new breed’ of content, which will force stronger narrative to ensure the ‘scene point of choice’ chosen by the viewer matches that visualised by the Director. Clearly, the utilisation of light, shadow and texture can be used to achieve similar effects without the need for shallow depth of field (as this is created naturally when scene points are viewed) and thus allow a full depth, in focus scene to be captured and eventually explored by the viewer.
What about convergence?
Of course one of the common questions that crops up is based upon the fact that you still shoot left and right eye content and therefore still need to ‘dial in’ convergence. However, key areas of difference exist in respect of H3D specific content.
1.Whilst it is possible to shoot in the same fashion as adopted for Stereoscopic 3D (with shifting points of convergence), with H3D, it is also possible to shoot with a fixed point of convergence. Whilst it may be regarded as ‘good’ practice to continue to ‘pull convergence’ based upon where the action is (after all, the aim may be to make the content compatible with Stereo and Holo displays), early tests with H3D suggest that this may not be the best way to ‘optimise’ the scene. Remembering that Holography affords the user a free choice for the point of focus, it becomes key to ensure that ‘scene scale’ is accurate. Parallax can always be adjusted with H3D display as long as the original scale proportions are maintained. Remembering also that parallax is the strongest depth cue, you can see that convergence still has a major role to play in capturing usable images. So, we can shoot with fixed convergence, as long as we have, and maintain the original scale proportions, we can adjust parallax to ensure a comfortable viewing experience for all scene points.
2.So, if you can shoot with fixed convergence, where do you converge? Well this is the point at which another key difference is introduced. If you imagine the H3D display as a ‘window’ onto your 3D scene, it is likely much of the action will occur behind the screen but with real depth (just like looking out of a window in the real world!). Therefore the most appropriate point for convergence is on the display plane (or zero/neutral parallax). Once again, ‘scene scale’ is critically important: knowing the total depth of a scene and which part of this scene will be behind the display will help set convergence for that scene. Once set for that scene, it shouldn’t be necessary to adjust it again, even when zooming in/out (as long as the original scale proportions are maintained, parallax can be adjusted).
The clue to why this is less critical is that convergence in Stereoscopic 3D is used to indicate a ‘level of depth’. With H3D, the level of depth is ‘chosen’ by the viewer as they naturally select a scene point in the scene on which to focus. The eyes, then, very naturally converge and focus on the same point (hence no headaches and no depth cue mismatch). This doesn’t mean it isn’t possible to create parallax errors (or painful divergence!) but the discipline here is to ensure that the maximum distance of a scene is always identified and in playback that maximum parallax means that at infinity, your eyes are parallel. This additional information needs to be captured at the point of acquisition for the content (whilst complex algorithms can make a good job of recreating it, the workload could be considerable).
So how is it done?
In essence, the most basic way of achieving this (the variable depth in the scene) is through the use of a Depth Map. In many high end CAD applications and other 3D modelling software, Depth Maps have been used for some time. They are essentially grayscale images which contain the ‘z’ axis data for distance from the focal plane to an object.
With these high end CAD packages, the Depth Map is often 32bit. The good news is that the level of ‘resolution’ required for H3D is lower and therefore an 8bit Depth Map is likely to provide the necessary level of granularity to reconstruct the scene with accurate depth. Many high end rigs are capable of capturing data indicating such information although it is yet to be seen whether or not this includes the Depth Map in the format required. As already described, one of the most important factors in H3D is the ‘scene scale’ and this is what is represented by the Depth Map and the main use of this depth map is for rendering the ‘reconstructions’ during display.
Some commercial organisations have already developed algorithms to recreate the Depth Map from Stereoscopic 3D shoots to enable full depth budget 3D content. These are likely to deliver the Depth Map necessary to experience 1:1 3D reconstruction to be shown on H3D systems.
Although most important for display purposes, as discussed earlier – it is key, where possible, to identify this metadata at the point of acquisition to ensure that the most can be made of it for scaling the ‘reconstructions’ for different size displays.
With this in mind, it is likely to be the case that the data overhead for transmission should be relatively low. As an example, it can be envisaged that Stereoscopic 3D content may be broadcast with the Depth Map as metadata alongside it. For viewers with a Stereoscopic 3D set, it will display in its normal fashion with a limited depth budget. For viewers with an H3D set, it will display perfect Holographic 3D reconstructions.
