Sun 27-Jan-13 02:41 AM | edited Sun 27-Jan-13 02:46 AM by icslowmo
I would agree with Jon. The LCD brightness plays a very large part in how an image appears to be exposed. The only other way to see this is with the histogram as Jon referenced to. If all bunched up to the left, then that would explain your under exposed images.
On that note, I tend to leave my brightness set to auto and seems to be close after I import images into LR4.3.
Also, as has been mentioned, active D-lighting will effect how the image is exposed. Generally I find it acts as a highlight protection mode so will under expose a bit and in software will pull up shadows. I leave mine on auto even though LR4.3 doesn't use the settings, pulling shadows a little if needed isn't much of a problem on the D800(E)'s....
Also I will add, this same thing can happen when editing on a bright (un-calibrated) computer screen. If the brightness is turned up too far, it won't match the standard print brightness of paper and your prints may turn out darker then you'd like.