As a wedding photographer I was really never interested in the D800. 36mp in ideal light for commercial jobs sounds fantastic but shooting thousands of images in a dark reception hall and having to deal with massive files horrified me. Because of this I purchased a D4 hoping for high ISO performance in a more manageable 16mp file. After I tested the performance of the D4 in low light and finding it was no better than the D3S, I am giving the D800 a second look.
The D2H, D3, D3s, and D4
The Nikon D3 was announced in August of 2007 and was a massive improvement from the Nikon D2 series. In 2009, Nikon announced the Nikon D3s which added about one stop of ISO performance and video functionality. Two years later Nikon released the D4, which many assumed would be a major jump in image quality (at least more significant than the D3 to D3s). Instead, the D4 has major improvements to the hardware, focusing, and video features but according to our test has very little improvement in image quality, if any at all.
D800 ISO performance
Now going back to the D800; the camera has not yet been released to the public, but there are many test shots from the camera floating around the internet. The general consensus seems to be saying that the D800 files will look better than D3 files if they are scaled down from 36mp to 12mp. This means that at 100% the D800 file will look noisier than a D3 file shot at the same ISO, BUT if you print the file or shrink it down for web the D800 file will actually look better than the D3.
If the D3S has approximately 1 stop better ISO performance than the D3 and the D800 will supposedly handle noise "better" than the D3 (when scaled down), why does the D4 cost twice as much? If these assumptions are correct, the difference in ISO performance between the D4 and D800 will be less than one ISO stop.
Is the D4 worth double the price?
Normally you might say that the D4 is worth double because it has a new focusing system, but in this case the D800 has the exact same system. You might say that the D4 has incredible features for videographers, like clean video output, audio monitoring, and lossless video zooming, but the D800 also has these features. I assumed the D4 would be around three stops better in terms of ISO performance but people are claiming that it will be less than one stop. So my question is: "Why then is the D4 $3000 more than the D800?" The fact that it can shoot 11fps? I have never shot more than 3fps in my whole career, so that one improvement has never appealed to me.
I thought it was strange that Nikon released a D800 and completely killed the need for their $8000 D3X. Now I'm beginning to think that the D800 may also kill the D4 for everyone except professional sports photographers. At this point I am going to buy both cameras and test them out before I make a decision. If the D800 really does perform as well as people say, I will be very excited to sell my D4 and get 2 D800s.