I've been shooting with the D800 for about 6 months now, and I've noticed that the in-camera previews appear much brighter and more properly exposed.
But when I load the RAW images into either Aperture or Lightroom (on the Mac), the rendered previews are very dark and often under-exposed. This has been quite vexing since when shooting the previews look great and the image appears properly exposed, but when it comes time to process the images appear very dark.
What might be the problem?
The camera will display the image based on your existing picture control settings, but these settings don't specifically mean anything when dealing with the NEF after the fact. Lightroom has some presets (I don't use Aperture, so I can't speak to it) for raw development that apply a "start point" that are quite similar to the picture controls, but are not quite the same. The View NX2 software supplied by Nikon will use the picture control settings from the camera as the information about your current camera settings are stored in the image file, but you can still adjust from there.
Bear in mind that every time you display the NEF, something has to interpret that raw sensor data into an image (unless it uses the embedded JPG). How it does that depends very much on the application doing the work. The camera and NX2 are going to be fairly similar, other applications will vary.
Also, make sure your display is calibrated. That's pretty important as the image may appear worse than it actually is.
The LCD brightness is normally adjusted for ease of operation and visibility. It's meant for basic review to make sure you have the data, not for exposure correctness.
There are two things you can do, though:
That is normal, if your image also appears brighter when you load the jpeg thumbnail from the raw file. That's how mine reacts as well.
It is because the in-camera settings clips more of the highlights and/or apply more gamma/brightness than your default setting in your raw software. The raw shows more accurately how you actually exposed the images and the in camera jpegs generator adds digital gain, clipping, and high gamma to compensate.
If your software works in 16bit mode it is preferable to keep the dark image as it is before you start tweaking on your own, so you have more power over the highlight areas, but if it is 8bit processing under the hood, you want to boost the brightness beforehand, like the camera does.
When you shoot an image, you have two choices to what happens to the images with respect to in camera process. RAW which does very little if anything to the photo and JPEG which the image is processed according to your camera settings. The JPEG image is affected by the camera's Picture Control (Nikon's name for the feature). There are several choices like Vivid, Standard, Portrait, etc. Each of these applies a process to the JPEG image. If you look at the setting, you can drill into each different one and see how it affects the image (pretend you want to modify the setting to see what it is, then cancel to exit without saving any accidental changes). When you shoot RAW, a side-car file is made of the image for viewing on your LCD screen. The side-card image is affected by the Picture Control.
When you load the RAW image into LR or PS, you are seeing an image that is basically untouched. Hence you need to adjust the image properties as you see fit. If you want to start your RAW photo (i.e. set a base on something close to one of the Picture Control settings), open the image in Camera Raw, and under the icon that looks like a camera, set the Picture Control there. It will be super close to what your camera would have done to the image in its JPEG processing. From there, you can tweak to you hearts content. Hope this helps.
