This will probably stir up some controversy, but here goes.
I spent the better part of today testing these 2 cameras. I was somewhat shocked, so I did it again indoors. Same thing. Now we await the REAL scientific tests like dpreview and DXO. Using an ISO 12233 chart as well as a Macbeth Color Checker I came up with the following results. I used the same lens (Nikon 24-70) on both cameras and adjusted the focal length for the same field of view (no easy task with the D7000 showing 100% in the viewfinder and my D700 only 96%). All shots were done in raw and converted using Nikon ViewNX 2.0.2. (I still am an Adobe Camera Raw fan, but I have to wait). The photos were compared with no sharpening and again with USM at .4 at 100% and 0.
My findings: The D7000 really needs to be compared carefully with the D700. The noise suppression is a good (maybe a little more) 3/4 stop better at ISO 3200 with the D700 . I did not test 6400 and higher because I never go there. The resolution is VERY slightly superior at all ISOs from 200 to 3200. Again, I did not test 6400 and higher.
1- The D7000 has a little better resolution then the D700 (expected if PRINT size stays equal).
2- The noise level of the D7000 at ISO 3200 was close, but not equal, to the D700 WHEN BOTH FILES WERE MADE THE SAME SIZE (either by upresing the D700 or down resing the D7000 in PS CS5. Comparing the two totally different file sizes at 200% gave a solid 1 stop edge to the D700. But we DON'T print that way. We print a certain size. The same scene printed at 16 x 24 inches would display about 3/4 stop less noise with the D700.
3- Dynamic range is more difficult to measure. First you need two files that have identical levels and curves. This is very difficult to do. Based on my attempting to "stretch" the DR in PS CS5, I would say the D7000 might well be equal to, or better than, the D700. This awaits real tests. Update: DXOMark gives the D7000 almost 2 stop greater dynamic range - but only from ISO 100 and fading to equal a little after ISO 400..
Here are the images. The width of the chroma noise files are severely cropped to 752 pixels wide for all 10 files. They were equalized so they will all PRINT the same size. The resolution files were cropped down to 2516 pixels and equalized. Remember, these files were made for comparison purposes only. Do NOT make any other generalizations, such as actual resolution in line pairs. A solid tripod was used on all shots. Timer delayed shutter release. Cloudy day. Charts hung on garage door. The lens used on all images was the Nikon f2.8 24-70 at f8 and various shutter speeds. Only the ISO was changed. All other variables were kept constant.
Here is an original image of the full scene. The shadow is from the plaster overhang above the garage door. Caution: Large file.
Resolution comparisons: (click on each image for a full scale version) Conclusion: The 16mp D7000 produced a VERY slight increase in resolution to the 12mp D700 at all ISOs. All information is copyright protected, but feel free to link to this page. Click on each image to make it larger, then click again for an even larger version.
Chroma noise comparisons: (click on each image to see a full scale version)
Conclusion: The D7000 produced approximately 3/4 stops more noise than the D700 at ISOs from 200 to 3200 when equalized for print size. All files started as raw files with noise reduction and sharpening turned off. They were converted using Nikon ViewNX 2.0.2. All information is copyright protected, but feel free to link to this page.
CONCLUSION: The D7000 is the best DX camera on the market today. It has a few advantages over my D700 as it is smaller, lighter, and can use smaller and lighter DX lenses. My favorites lenses at this time are the Nikon 10-24mm, Nikon 16-84, Nikon 70-300, and Nikon 300 (FX). With a 100% viewfinder you are no longer guessing at coverage. The viewfinder appears just as big and bright as my D700. That's nice. It also uses a true 14 bit!
Is it a better camera than the D700? No. However it might well be a better camera for some users! I decided to stick with the D7000 for two main reasons - smaller and lighter using smaller and lighter glass. I also appreciate the increased dynamic range as I do a lot of post processing and tend to really push the raw files pretty hard.