Nikon has actually launched two DLSR cameras today. The first is the Nikon D800, the second is the D800E, "the ultimate alternative", the "special edition", as Nikon refers to it.
The D800E is based on the D800. Actually, it's the same camera, with all the same features, except for one major difference. The Nikon D800E has had the optical filter modified to remove the anti-aliasing characteristics.
The anti-aliasing filter, sometimes known as the optical low-pass filter, removes unwanted interference, such as moiré patterning, that can occur on particular subjects, especially common on textures such as meshes or patterned surfaces - clothes, brick walls or netting, for example.
In digital imaging, this often happens because the grid of the sensor and the grid of the pattern have different alignment or the resolution of the sensor isn't high enough to accurately sample patterning in the scene, or both. Anti-aliasing filters are generally included in all digital cameras in some form, with medium format cameras being the notable exception.
The trade-off for avoiding the interference in images is a slight reduction in sharpness and often brightness. For most users, it's an acceptable compromise, but for those few that want the best possible results from the 36.3-megapixel sensor, then the Nikon D800E might be of interest.
To demonstrate the sort of difference you can expect, Nikon used the image below, which is a crop from a snowy mountain scene (resized here, but you can still see the difference).
While you won't have to pay the same sort of prices as you would to get an AA filter-free camera of the PhaseOne or Hasselblad variety, there is a small premium. The Nikon D800E will cost you £2689.99.
When asked what proportion of buyers would opt for the D800E over the D800, Jeremy Gilbert, group marketing manager of Nikon UK, said he thought it would be "around 10 per cent". Nikon D800E availability will be through selected retailers, in particular those who can better service the needs of advanced photographers, from 12 April 2012.