I have D 700 and D 7000 and with a friend, having D 800, we went together taking pictures in Santa Luce, Tuscany, Italy, in a very nice morning, nothing stretching the ISO or dinamica range capability of both cameras, just a very normal day with very normal light .
The reason of that joint taking of pictures was that I am an amateur photographer, taking generic pictures, including landscapes, the D 700 is not certainly the best camera for landscape (low resolution) and I WAS, not anymore, willing to purchase the D 800 and I was asking him to let my try the camera.
Myself took around 100 shots with that D 800, and during that time, I changed the same my lenses from D 800 to D 700, so taking the same shots, at distance of just minutes, same light, same everything, including the lenses, my 14 – 24 mm, my 70-200 VRII and the 24 -70 on both cameras.
I mostly print in A3 and A3+, and I did all the work, from camera to print, on 6 of those D 800 shots, and 3 on D 700, printing both, made with D 700 and D800, quite similar picture on my Epson 3880, small printing size, A3 (around 30 x 40 cm).
I am taking picture and printing myself since 42 years, I am an amateur photographer, on digital cameras from 4 years, expert in digital postproduction, applying proper Capture Sharpening in ACR, Artistic Sharpening as Mr. B. Frazer dictate in his “Real World image sharpening”, with limitation at the extremes of the range, on black and highlights, and applying Print Sharpening, together with proper interpolation, including grain, with Alien Skin Blow UP and the expert people watching at my prints, all of them, they say that the quality of my printing is quite high and quite OK.
Myself and others, we basically cannot detect any difference, with naked eye, from prints on shots taken by D 700 and D 800, basically the same picture, on A3, observed them from half meter distance, whilst if you go and check with a magnifier or check carefully at short distance, around 20 cm and you have good eyes, some more very tiny details can be seen on D 800, but the entire picture, in a real view, look pretty the same.
But……there a “but”, and, in my very personal opinion, it is a very important “but”.
The Nikon zoom lenses that I have tested on D 800, 14-24, 24-70, 70-200 VRII, all of them, unless you close well the diaphragm at around f 6.3 – f 8, they are not very exciting on that camera ,not at all, the borders are weak with 14 -24 and 24 -70, better with 70 -200, and with that camera, you can detect a minimum misalignment of a zoom, which is almost normal in a zoom and which cannot basically detected on D 700.
Moreover, if you stop very down the lenses at f 16 – f 20, which is normal for picture with wide angles for a very deep DOF, a with the subject in the very closed distance and the landscape in the back, and this pictures are very normal in landscape shooting, the pictures taken with D 800 is not so sharp like the pictures taken by D 700, and already in 30X 40 cm printing you can see this, no gain at all in respect of D 700, if not a loss.
On this prints, with deep DOF with D 800 and D 700, Details of ACR and Smart Sharpen in PP where working in deconvolution.
I am working mostly with zoom, after almost 40 years with primes on film, I went on zoom on digital: I will not change back to primes for a camera to shot at large apertures, whilst if you close the diaphragm around f 16 or more, the picture will be not better than the picture taken with D 700 on that relatively small A3 print size.
D 800 could certainly be better in large formats printing, it looks even better on monitor, but monitor is monitor and printing is printing: on A3 it looks pretty like the D 700, and at high number of F stop even not at the same level of D 700.
This is my modest and limited in number of prints experience with D 800 + 14 -24 , 24 -70 and 70 -200 VR II, just my experience, and I will not shift from D 700 to D 800 as the majority of my prints are in A3.