sometimes i just wish i know the technicalities of my camera like you guys.i have no idea what you are referring to in the last sentence.:cry:
I'll see if I can explain the two items that I was talking about in that last sentence - might be a bit hard and end up being long winded.
First item, you know about white balance right ?
To achieve white balance, usually digital cameras electronically multiply the signal values from the red and blue channels (you can see this in the exif information in your images, you'll see a red balance and a blue balance value, each of these is a number, what the camera or RAW converter does is multiply the values from the red or blue channel with that number). So your histogram that you see is dependent on your white balance setting.
On Nikon cameras (I am not aware of other makes of camera where you can do this), you can load a special white balance setting where these numbers used to multiply the red and blue channels are set to 1 - thus with this setting, you can see a more accurate representation of the light your sensor is being exposed to - thus a more accurate histogram. (This by the way, can help you understand why certain lighting conditions produce more noise than others - for example in certain types of incandescent light, the blue channel is actually 2 stops underexposed compared to the green channel on certain cameras, and also why some people use colour correction filters to reduce noise in shadows etc)
Second item, you know about tone curves right ? That setting on your D200 under optimise image where you can set the tone curve to Normal, Auto, More Contrast, Less Contrast or Custom ?
What's neat about Custom is that you can load your own custom curves (like going into the Curves tool in photoshop except you can do it in camera), and as you may be aware, some users have created their own for different cameras to reduce the amount of PP work they need to do to the image. But the tone curves can affect the histogram you see as well. To get an un-modified representation of your histogram, you can load a linear custom curve - ie. one that is a totally straight line going at a 45 degree angle from the bottom left corner to the top right hand corner.
