I’ve wanted to piece together bit and pieces about understanding digital photography for awhile. I am going to start piecing together little photography tutorials in the hopes that someone may stumble across it and learn something new!
Today - The Histogram!
Most digital cameras, from the simplest point-and-shoot to the most sophisticated digital SLR has the ability to display a histogram directly, or more usually superimposed upon the image just taken. On most cameras though the histogram display takes place on the rear LCD screen, and most cameras can be programmed to do this both on the image that is displayed immediately after a shot is taken, or later when frames are being reviewed.
In a Canon camera (it should not be too much different in other cameras) you can see you histogram pressing the INFO button when you are on the VIEW mode.
The beauty of a histogram is that the small LCD display on your camera is not really big enough to give you an great review of a picture and you can often get home to find that you’ve over or under exposed an image. After each shot I normally look at the LCD screen for two reasons: to see the sharpness of the image and to look at the histogram in order to see how well exposed my photo is.
Your eyes should be the final judge always, but it’s nice to have the histogram there to help you out when you can’t judge how well exposed the picture is. The higher the graph at any given point the more pixels of that tone that are present in an image. So a histogram with lots of dark pixels will be skewed to the left and one with lots of lighter tones will be skewed to the right.
For example:
This is the histogram of a under exposed picture:
This is the histogram of a over exposed picture:
This is the histogram of a correctly exposed picture:
And of course I have to throw in the edited version of this image because I just adore Miss R.
This is a very very brief example of what your looking at when you see your histogram pop up. The video below explains in DETAIL what exactly your histogram is telling you: