Originally Posted by
WIlliam Maroldo
Hi Nancy. A few things about histograms, from my point of view of course. I am assuming you are shooting RAW. First of all take a test shot and look at the histogram. Ignore everything thing other than the far right side of the histogram. The right side is absolutely the most important; this is where clipped highlights occur. Theoretically these are whites that contain no digital information. However in the real world it is possible to "recover" detail from this area if you didn't get too carried away. Use exposure compensation or adjust shutter-speed, etc, to get the histogram where you want it by taking test shots, and your good to go. Delete your test shots.
Overexposed images contain more digital information than underexposed images. Compare file sizes of some of your own over and underexposed images, and you'll see what I mean. More information translates into more detail.
The goal, which is quided by the histogram, is to overexpose images to the point the clipped highlight warning appears (the blinkies). A few blinkies, but not a lot, is perfect IMO. As you get more experienced in this type of photography, you will get a feel on how much overexposure your camera can handle, and some cameras can handle quite a bit.(which means recovery is more likely)
In post processing you will take an image which actually looks "washed out" and drop the exposure to normal. If there are still "red areas" which Adobe Camera Raw uses as a highlight clipping indicator, use the "recovery" slider to eliminate them.
Note; since when shooting you have shifted the entire histogram to the right, you leave out much of the darker pixels. These are where digital noise exists to the greatest degree, and since you have left them out of the capture, you have far less noise! This means you can shoot at much higher ISOs than you did when you didn't "expose to the right"! regards~Bill
One more thing; you are only worried about the exposure being correct for your subject. If the background is too dark or light you have no choice but to deal with it is post-processing. Because the background will effect the histogram, and you aren't exposing for it, it is one reason the actual histogram graph is not very useful.