I just got a D600 a couple weeks ago, and yes, my RAW files are coming out a bit dark in Aperture. Perhaps Aperture's D600 contrast curve needs some adjustment, but I think the bigger issue is the default black point setting.
For my D60 RAW files, Aperture's default black point value is 3.0. I sometimes back off on that a bit, but it's a good default. On the D600, Aperture's default black point is 5.0, which I find a bit too dark, more often than not. I'm guessing the higher default black point is intended to compensate for the larger dynamic range of the D600's RAW files (14 bits per channel instead of my D60's 12 bits per channel), but I think they have erred a bit on the dark side.
In any case, it's not too hard to fix. My suggestion is to turn on the hot/cold overlay, then scale back the black point until any blue overlay areas have disappeared (you may want to allow some small isolated blue areas to avoid weakening the overall contrast too much). I also recommend going into Preferences > Advanced and setting the hot/cold thresholds all the way to 100% and 0%, respectively; this makes the hot/cold overlays only appear where pixels are actually clipped.
Fortunately, dark areas that look completely blown are actually totally recoverable, and usually pulling back on the black point is all you need to do. In some cases you might also want to add a tiny amount of contrast (even 0.01 is quite a bit).
This is what I've found so far, anyway. I still have a few things I'd like to test to get a better picture of what's happening here:
- Enable RAW + JPEG (FINE) and compare RAWs to the JPEGs for the same shot
- Try capturing some 12 bit RAW files (there's a setting for this) and see how those look in Aperture (is the default black point still 5.0?)
- Install the current version of ViewNX and see how Nikon's own RAW processing compares (the RAWs should end up looking the same as the JPEGs)
- Check out all this stuff in Lightroom (I don't really use LR, but I do have it installed, as it's included with Adobe Creative Cloud)
If you guys have done comparative testing of any of the above, I'd be interested to hear about your results.