blown highlights
or "learning to use the basic image controls on my camera" or "histowhat?"
shamefacedly i have to admit i mostly point and shoot with my nikon. i keep it set on P so i have fingertip (well, thumbtip) control of shutter speed and aperture, i do adjust exposure compensation and the focus bracket, i change iso and swap out lenses, but otherwise i don't get into the intimidating array of tweaks and adjustments available.
i take a lot of backlit pictures (small house w/windows each end) and while i know i should be using fill-in flash i find it too intrusive. so i use centre weighted metering and crank up the exposure for the faces and get a load of blown highlights. now i'm not sure if there is much fixing to be done in this situation save finding a better angle, but the search for some answers has been educational at least. lets take it as read that every sentence from now on starts "i never realised that..."
the d40 has a "highlight" preview mode that flashes areas that are clipped. you scroll down with the controller during playback to get this view (along with all the other info viewing modes) and all pictures will play back as you take them with this view until you select another. what you do with this information i'm still slightly sketchy about, i guess you just take another shot until it stops flashing, or you're happy that the flashing areas are non-critical (i.e. not on the baby's face :roll: ).
on the way to the flashing highlight view i stumbled on the histogram too. i assumed that a well exposed picture will have the curve towards the centre, but that was the long and short of my knowledge until i read this article at the ever informative-to-the-point-of-brain-ache luminous landscape. now i know that histograms "just are" :? it seems that reliance on histograms is mostly a hang over from when preview screens were rubbish, but handily the D40 has a large bright screen that provides an accurate preview of the image. i like ken rockwell's take on it: "The best way to evaluate exposure is to look at the picture, not a histogram. Histograms are a way to measure exposure more objectively for those who can't see very well." :D
ken is very keen on colour histograms though, since the red channel is likely to blow ahead of the others, and i can attest to the resulting weird colour effects. on the D40 pressing ok during playback brings up image adjustment options. choosing filter effects>color balance brings up an rgb histogram (i.e. a separate histogram for each of the 3 colour channels). again the camera remembers your settings so you can just press ok 3 times during playback to bring it up.
it seems one thing i can do that should definitely improve my highlights is to stick with lower isos, which apparently have greater dynamic range. i'll also have a play with the different metering modes now i have a slightly better idea of what they do.