I'm the editor of a web magazine and we did the big camera comparison test a year ago. We recently tested a H3D39 against a D800 in terms of resolution, colour, usability, etc. and also commented on it's use as a cheap entry point into a technical camera system (we consulted a few retailers and people who have actually researched and gone through this route) and I wondered whether a few excerpts from the test would be of interest to the forum? If I'm not supposed to post anything relating to a commercial activity here just let me know or delete the thread.
Issue Fifty Six | On Landscape
Our results suggest that the two cameras are producing almost identical results depending on how you compare the slightly different aspect ratios.
If you want a 3x4 image and would crop pixels off the D800 to get it then the H3D39 produces a slightly sharper and smoother image.
If you want a 2x3 ratio image and have to crop the H3D39 then the D800 ends up just a bit sharper (although very close) with smoothness on a par but possibly with the advantage to the H3D39 (at base ISO).
Now the interesting thing is that colour accuracy was a toss up. The H3D39 got some flourescent materials more accurately but the D800 got foliage a hell of a lot better (the classic yellow greens of the H3D39/P45 chip showed themselves). The H3D39 had problems with a later evening sky where the colours went slightly odd but then again the D800 showed much too strong cyanic blues.
We used a Sony A900 in one of the tests as a colour reference (that camera is just stunning for colour) and the resolution showed a significant drop from both cameras even in print.
The H3D39 didn't like rainy weather though and showed some sync issues (magenta splurges).
The article is subscription only but here's a few samples of comparisons
The first shows the advantage to the H3D39 when cropping the D800
The second shows the sunset shot with the colour comparison
The third shows the difference in foliage colours
The first comparison also includes a frame taken with Portra 160 on the 645 film back. The 645 film back has a disadvantage because we were using the same lens as the digital back test whereas in fact the film has more surface area. Even so it's obvious that film can't compete at this scale (scans done on a well tuned Howtek drum scanner).
I would expect you'd need 6x7 for film to compete. It should be noted that transparency film retains more detail in a scan and we'll perhaps repeat the test with Provia next time and try to find a subject where we can zoom in/out to keep area the same.
The last test includes the Sony A900 for a colour reference. Just click on the 'names' underneath the picture to choose your comparison.
We also printed the results at various sizes to see if there was any visible difference when shown to members of the public and the answer for our particular test was that there wasn't any in terms of sharpness (the public don't tend to be great at this anyway). The photographers we showed the test too couldn't tell the difference when the prints were separate, only when they were shown side by side. We printed up to 20x24 and printed a sample at 40" long edge and 60". The cleanliness of the H3D39 showed through at 60" when compared side by side though when cropping the D800. I think this would be a very close thing if you cropped the H3D39 to give a 2x3 ratio image.
I'm happy to answer questions about the test if anyone is interested?