I’m using Aperture – and sometimes Lightroom – to work on the RAW files I shoot with my Nikon D300. When I open an image for the first time, the preview will show me the JPG thumbnail in the RAW file first and then show the RAW file as interpreted by Aperture, which is usually a lot flatter.
It also seemed to be quite underexposed a lot of the time. I didn’t think much of it because I thought it was just the difference to the D90 I used before, which is said to have a tendency to overexpose.
Today I found the real reason: I had switched on Nikon’s built-in Active D-Lighting functionality which claims to “comes to your rescue in high-contrast situations when previously you’ve been forced to choose between sacrificing shadows or highlights. By automatically regulating the dynamic range of a scene, such as clouds, it allows you to depict shadow details while preserving highlights. In this way, both shadowy and bright sections are more pleasantly detailed and exposed, to achieve the desired contrast.”.
Well, it seems this comes at a price:
“Active D-Lighting underexposes the image to preserve highlights, therefore damaging shadow detail and increasing noise overall. It’s a great thing if you’re shooting for print and need quick results, otherwise it’s better to just leave it off and do your own post-processing as needed.”
“If you shoot raw and use software that is not made by Nikon, you must turn off Active D Lighting. Non-Nikon software does not interpret ADL information, and all you get is an underexposed shot.
Personally I never turn it on. It adds to shadow noise, and the newer Nikon already have excellent DR that gives you quite a lot to work with in Aperture.”
(From the photo.net Nikon forum)