Sony NEX-7 RAW
Sony NEX-7 RAW Comparison
We often look 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 de-mosaicing 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. (That said, looking at the ISO 6,400 and above examples below, it's clear that dcraw's de-mosaicing approach does have some tendency to produce rectilinear artifacts in response to high noise levels.)
See crops below to compare the NEX-7's RAW image quality to some leading SLT/SLRs: the Sony A77, Canon 60D and Nikon D3X.
Here, we can see the Sony NEX-7 does produce RAW files with less noise than the SLT-A77 which we assume uses the identical sensor, so we conclude the light lost through the A77's transflective mirror is to blame, requiring the A77 to amplify its sensor output more than the NEX-7 at the same ISO. The NEX-7 doesn't perform as well as the 18-megapixel Canon 60D at the pixel level, though that's not a surprise given the 60D's larger photosites (4.3µm vs 3.9). The Nikon D3X which was included here because it has similar resolution (24.5MP) also does quite a bit better than the NEX-7, but at over six times the cost, it's not exactly a fair comparison. The D3X is also the only full-frame camera here, giving it the advantage of the largest photosites of the group at 5.9µm. (Note that the D3X is capable of ISOs as low as 50, not shown here.)
See crops below to compare the Sony NEX-7's RAW image quality to a few recent compact system cameras.
Above, we can see that the NEX-7 doesn't do quite as well as the Olympus E-P3 at the pixel level, at least up until ISO 1,600 where the Sony starts to pull ahead. Keep in mind the E-P3 uses a 12.3MP sensor with a pixel pitch of about 4.2µm versus the NEX-7's 3.9. The Sony's nearly double pixel count will certainly help it print much larger than the E-P3 at the same ISO. The NEX-7 clearly does better than the Panasonic G3 at all ISOs. That's not a surprise given the G3's smaller 3.8µm photosites. The 20-megapixel Samsung NX200 does quite well, though, performing at least as well if not better than the Sony in terms of noise, with its larger 4.3µm photosites.