This is why I read Ken Rockwell:
Who else would even think to do something like that? And it’s a genuinely interesting comparison, too, not just because I am a D40 user, but for a more substantive and technical reason: If you do the math, it turns out that the individual photosites on the D40 and the D3 sensors are pretty close to the same size. That means what you’re seeing in these photos, if you compare strictly the D40 and D3 shots, is a pretty good comparison of how Nikon improved its sensor noise handling technology between those two generations of cameras. It’s really a striking illustration of how dramatic the improvement was, at ISO1600 and beyond.
It’s also a pretty good exemplar of how well the D40 handles itself at ISO 400 or even 800. (The colors do tend to be a little duller on the D40 shots, but I’m guessing that’s because the D3 and D3100 have Nikon’s Picture Control feature, while the D40 doesn’t. That would mean the D40 is using different JPG conversion parameters, so it’s not surprising that the colors look different.) The D40 ISO800 shot looks almost as good as the base ISO200 shot. This matches my own experience: I’ve found that ISO 400 is quite usable when an extra stop is needed for wildlife or what-have-you, and I can even use ISO800 to get acceptable results if I need to. Yes, there is more noise at that sensitivity, but as Rockwell says, it’s not just about the noise. Noise can be dealt with. The level of detail retained in the photo is the key issue, and it appears to be roughly the same at ISO400 and 800, with ISO200 having a bit of an edge. This supports my belief that, in terms of bumping up the ISO sensitivity, the D40 is the best of its generation of cameras (namely the D100, D70, and D50). I would also guess it handles those speeds better than its immediate successors (namely the D40x and D60…not so sure about the D3000, though).
Pro-D40 ranting aside, the other interesting thing about that page is how clearly it demonstrates that the D3100 is a step up from the earlier generation of camera. It’s only at ISO6400 that the D3 begins to look significantly better than the D3100. Compare this to the D40, which is essentially crap at ISO3200–in fact, it doesn’t actually have a proper ISO3200 setting, it’s actually “HI 1”, and it can’t shoot at ISO6400 at all.
Now if only the D7000 was out so it could be included…