Ever watched a program on photography and heard commentators say a shot is "overexposed"? In a lot of instances, this assumption comes from just glancing at the image or the image's histogram. Here's the thing. The histogram in photography isn't quite the same as the one you use in your day-to-day marketing or forecasting presentation.
What is a histogram?
In photography, the histogram is used as a reference to help you understand the levels of light and color in a particular image. Analyzing image exposure is usually the primary reason for referencing a histogram. The way a photograph's histogram is laid out, you can quickly grasp what's going on with the image's levels of black, shadows, midtones, general exposure, highlights, and white. If you look at the graph in Figure A, you'll see vertical lines that delineate these levels of a particular image. As the white bar flows horizontally across the histogram, it lets you know that the image hits the marks for all the levels previously mentioned. The higher the peak, the more intense the particular level is in the image.
The black levels (denoted on the left) are high, the exposure level is low, and the highlights (denoted on the right) are about midrange in intensity. Like any tool when it comes to art, you shouldn't always depend on it. Just reference it. Let me explain why.
The "perfect histogram" myth
I've seen, read, and heard discussions on what the "perfect histogram" should look like. The claim is to have a distribution across all light levels in the image, as well as to have slightly increased exposure, similar to the image in Figure B.
I can't say I've agreed with this thinking, because many variables can affect the image's histogram. The camera settings and the scene you're shooting directly affect your histogram before you even click the shutter.
Sometimes, the beautiful image captured doesn't have the so-called "perfect histogram." For example, classic dark images found within the chiaroscuro photography will have higher black and shadow levels than exposure levels. Capturing an image of a bird flying across a sunny sky could have higher white and highlight levels because of the intense light coming from the sun or the camera sensor's reaction to the bright white clouds. It all depends on the composition.
When to reference your histogram
You can check your histogram during your photo shoot. As the image is saved to your camera's or phone's storage, you can generally view the file. For example, Canon allows you to click the Info button in the menus of its camera to display the histogram of the recent image taken. There's even an option to view the RGB (red, blue, green) levels in a seperate histogram. On your mobile phone, you can display the histogram in the editor, such as Snapseed or Lightroom. After checking your histogram, you can make any necessary in-camera adjustments and complete your photo shoot. You can also reference your histogram during post processing and make adjustments to enhance your image.
Get more familiar with the histogram. This tool can really help you understand the final output of your photos. Dive in and produce some awesome creative works!
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Do you reference a histogram in your photography work? Share your tips and advice with fellow TechRepublic members.
Ant Pruitt is an IT Support Professional with a passion for showing the non-geek how great technology can be. He writes for a variety of tech publications and hosts his own podcast. Ant is also an avid photographer and weight lifter.