Nikon D810 is just announced by Nikon, take a look at the Major core difference below.
Nikon never said that they have used a new image sensor inside Nikon D810 DSLR, the only one new thing (noticeable) is the new Expeed 4 image processor inside Nikon D810 DSLR.
Due to the help of New Expeed 4 Image Processor and Improved Software Program (Image decoding, AF.. etc) you get
- Nikon D810 pushes it low ISO limit to 32 and high to 51200.
- 12 bit un-compressed file support
- More picture control options
- Highlight Weighted Metering now available in Nikon D810.
- Spot White Balance when using Live View
- Redesigned Sequencer/ Balancer Mechanism added for Image Stability.
- Electronic Front-curtain Shutter, Yes Image sensor acts as the front curtain reducing internal vibrations Activated with Custom Settings or when using Live View
- Group Area AF now possible with Nikon D810 (Yes Five AF sensors used as a Group Optimized for subjects located within an area covered by the “Group)
- Full HD Recording at 60fps now possible
Other improvements include bit high-resolution LCD display unit, optional wireless control and better battery life.
Verdict: For new users we recommend you to buy Nikon D810 camera and for Nikon D800E users we recommend you to wait for Nikon D900.