Nikon D7000 High ISO RAW Image Quality
We've recently started looking at RAW files converted with dcraw, an excellent freeware raw converter. dcraw usually offers timely support for the latest cameras, but more importantly, it does not apply any noise-reduction, sharpening or other corrections such as geometric distortion correction to the output files as some other converters do. There will always be differences between RAW converters, in terms of the sort of demosaicing algorithms they use (the processes by which they convert the separate Red, Green, and Blue data sets to an array of full-color RGB pixels), but dcraw seems to use a fairly generic algorithm that delivers good sharpness with relatively few artifacts, and can be counted on to not apply any noise reduction if you don't want it to.
See for yourself how the Nikon D7000's high ISO RAW files compare to those from the Canon 60D, Pentax K-5 and Sony A580. Click on any of the crops below to see the corresponding full-sized image.
Here, we can see the Pentax K-5 clearly produces the cleanest looking RAW files, though it appears to be applying some noise reduction at higher ISOs (above 1,600) that can't be turned off. The noise reduction applied is pretty subtle, though, nothing like the heavy-handed approach used in earlier Sony SLRs. Still, it's something we'd rather not see in RAW files. The Nikon D7000 comes in second in terms of noise performance. The Canon 60D comes in a close third, but its slightly higher resolution should help when it comes to printing at the same size. The Sony A580 places fourth, with the highest noise levels of this group, though it's still quite competitive.
Here's a comparison of the D7000 with its immediate Nikon siblings:
Here, we can see noise levels from the Nikon D7000 are slightly improved over the D90, and even better compared to the D300S. Very good performance from the Nikon D7000, especially considering the smaller pixel size.