Originally posted by ROBEFFY Most pro photogs including him do not use the histogram.
And the majority of those "pro photogs" started with film and have no idea what a histogram is. I took a class from a local pro a few weeks ago and he checked the histogram and adjusted for nearly every shot. He noted that for him it was the best thing ever invented as he could get his shot perfectly exposed. He is a landscape shooter, so plenty of time to contemplate.
The shape of the histogram is less important than the horizontal boundaries. You want some data in as much of it as you can. Bright contrasty days that is easy, gray overcast days you might not have anything on the edges but that is what there is.
Many subscribe to ETTR which means Expose To The Right. Basically try to get each shot with some pixels of the histogram right up to the right edge WITHOUT going over. Anything going up the right edge is overexposed and lost. But you need that right edge data so expose so that you are right up to the line. But remember on a day with white clouds, or with snow in the scene you will have some pure white so you will have pixels up the right edge.
When shooting quick I turn on the 'blinkies' or the overexposure indicator on the preview screen. Then I expose so I have just a few 'blinkies' in white areas. Say there is a white cloud in the scene, you should have a couple blinkies in the whitest part of the cloud, because it is pure white.