The long anticipated D800 from Nikon has arrived, and while it's not quite a D4 in a D700 body like many were hoping for, it does sport a humongous 36.3-megapixel full-frame (FX) sensor (15.4 megapixels in DX format). Nikon says it's the world's highest effective pixel count among interchangeable lens DSLR cameras equipped with image sensors conforming to the 35-mm film size, and we won't argue the claim.

Low-light photographers will want to temper their enthusiasm. Nikon limited the standard ISO range from 100-6,400 with additional support for equivalents of ISO 50-25,600 in Hi2 extended mode, enough to the job done in reasonably lit environments, but well short of the D4's insanely high 204,800 top-end ISO rating.

That doesn't mean there isn't a lot to like on the D800. Nikon equipped its latest DSLR with a new EXPEED 3 image-processing engine that's supposed to be faster and offer better performance than before. It has a new 91K-pixel RGB sensor, and when a human face is detected in the frame, the D800's 3D Color Matrix III technology kicks in to make sure the face receives the proper exposure with regards to available backlighting.

Other bullet points include a 51-point AF system, 3.2-inch LCD monitor, Full HD 1080p video recording, CompactFlash and SD dual memory card slots, and support for USB 3.0, all of which is packed in a lightweight and durable body that's water- and dust-resistant.

The D800 will ship in March for $3,000, followed by the D800E (same camera but with an optical low-pass filter baked in) in April for $3,300

Nikon D 800 vs D800E - What is the difference?

Almost every camera has a built in Low pass filter that introduces a slight blur to each pixel in order to reduce the moir'e effect or cross hatching.

This slightly degrades the image quality but gets rid of unwanted cross hatching patterns across the image.

The Nikon D800 E come with the low pass filter removed or rather not installed, This is an important feature for Professional Studio and landscape photographers who are well experienced with the Low pass filters & its effects thus helping them to create sharper & better quality images.

Nikon D800 Technical specifications

Also here is a  Nikon D800 Official promo video 

sources:maximumpc.com, dpreview.com, pcworld.com, youtube