Hierarchy of Light Fields [Levoy]
8D: Refractive/reflective environment
5D: Plenoptic Function (Ray)
4D: Lumigraph / Lightfield
4D*: Environment Matte (single view)
3D: Lumigraph Subset
3D: Concentric Mosaics
2.5D: Layered Depth Image
2.5D: Image Based Models
2D: Images and Panoramas