Photog Tip of the Week: Love Your Histogram with Ann McRae
Today’s Photog Tip of the Week is presented by Ann McRae, longtime Canadian Smugger, Pro shooter and Support Hero extraordinaire. If you’ve never received an awesome help reply from Ann, you’re missing out! Your histogram can make or break your image. Knowing how to read your histogram will dramatically help you get it right in-camera… which will improve the shots you take and increase your number of keepers. Here’s the scoop straight from a pro who knows.
What’s a Histogram?
The histogram is a graphical representation of the brightness of your image. It shows the amount of dark areas on the left and the amount of bright areas on the right, which means that you can make decisions about the settings you’re using to shoot a scene.
The histogram is your key to getting the very best possible photograph in-camera.
The good news is that almost every digital camera released in the last few years has the ability to display a histogram on the LCD. You may be surprised at the difference between the information in your histogram and the JPG preview of your images on your camera’s LCD. Many folks overlook the fact that the LCD screen is backlit, which makes the image look much brighter than it actually is. Watch the histogram instead and don’t be fooled!
Expose to the Right… but Not Too Much
The “ideal” histogram shows mid tones that are evenly distributed between the darkest and lightest points in the scene. But remember that a histogram is just a graphical representation of the data in the photograph, so there’s no real right or wrong!
The following two photos show properly exposed scenes but the histograms in the upper right corners look dramatically different:
In the above photo, there is a broad range of colors and therefore the data is distributed across the whole graph.
On the other hand, almost all of this above scene is bright white snow so most of the data is pushed to the far right. Kelso is properly exposed and you can see plenty of detail in his face.
Why You Should Get it Right
Don’t overexpose the scene. The histogram for this kind of shot looks like it has a big hump on the right, possibly even falling off the right side of the chart. Some cameras display blinking areas on your LCD preview image to warn you that your images are too bright. Data in the overexposed areas is lost and will simply be flat white with no details. Here those areas are shown in red:
Don’t underexpose the scene. A histogram with the majority of the information to the far left (dark shadows) is underexposed. When you do this, you run a higher chance that prints made from this photo will turn out dramatically darker than you expect. This is because you’re processing and editing your digital photo on a backlit monitor or LCD, which is much brighter than a physical print that is lit with reflected light. You may be able to pick out details in the shadows when looking at an image on a monitor, but those details will be lost in a print.
(Bonus: Find more technical reasons for exposing to the right explained over at Luminous Landscape.)
Here are two versions of the same shot with completely different exposures. See how the histogram sits in each one?
Histograms for Effective Post Processing
Of course, once you have a well exposed photograph you may still want to do some post production work to be sure that you are getting the most out of the data that you have.
Bumping the exposure, fill light and tone curve of this example image just a tad pushes the bump from the middle of the histogram to the right, and really does a lot to enhance the image:
Once again, watching your histogram really pays off. Learn to love it and use it!