> >So what you are saying is . . think of the histogram as >"roughly" and experiment, but compensation adjusting >for "over exposure" is an inappropriate >"misunderstanding"? Seems therefore that the best >approach is to Spot Meter in Manual Mode off something in the >scene that is Neutral and assume the camera sensor sees that >as 18% grey? I respect your knowledge greatly, but I have >slipped further into the circle of confusion.
Spot metering off of something that's medium grey can work well if the lighting in the scene is consistent or if the object you're metering is in bright light and you're trying to do minimal post-processing (think jpegs). If you're shooting raw and you'd like to have an image with the most flexibility for post-processing, including the greatest dynamic range and the least noise in the shadows, you simply want to keep your histogram (preferably the RGB one) shifted as much to the right as you can without blowing highlights. This won't necessarily result in an image that looks good on the back of the screen - it might very well look too bright - but you'll be able to get a lot out of it in post-processing. How you get this result can be done a variety of ways (matrix, spot, center-weighted); the important thing is interpreting the results and then adjusting the exposure accordingly.