Canon 7D Review
Canon EOS 7D 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. (We found that Adobe Camera Raw still applies some limited noise-reduction when its NR settings are set to zero, and it also applies other corrections depending on the make and model of the camera). 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.
Below are crops Canon 7D high ISO RAW files compared to RAW files from the Canon 50D, Nikon D300S, and Pentax K-7, converted with dcraw.
It's actually surprising to see how similar these cameras perform in terms of high ISO RAW file noise. The 18-megapixel Canon 7D compares very favorably to the others in this group, despite having the smallest photosites. (The Canon 50D has 15.1 megapixels, the Pentax K-7 has 14.6 megapixels and the Nikon D300S has 12.3 megapixels.) Also notice the slight improvement that can be seen compared to the Canon 50D, with fewer bright pixels and less horizontal banding at higher ISOs.
Note: For details, test results, and analysis of the many tests done with this camera, please click on the tabs at the beginning of the review or below.