One of the main advantages of digital photography over film photography, at least in my mind, is the ability to view the histogram shortly after taking the shot. While viewing the image on the LCD is obviously an advantage as well, it's difficult to tell if the shot actually turned out based on a small image on a 2-3" LCD. An example histogram from Luminous Landscape A histogram shows you how many pixels in the image (shown on the vertical axis) are at each intensity level (0-255 typically, shown on the horizontal axis). If the histogram is bunched to the left, that typically means the image ...