Have you heard of the term ‘depth of field’? It refers to the amount of area in a photograph that is in focus. When you are taking a portrait of a person, having the head and shoulders sharply focused is important, and it’s even better if the rest of the body, and the background, is blurred.
Making the scenery behind the subject out of focus means you remove any distractions from the image…the viewer is directed to the area you want them to look at. However, landscape photographs work best when you can clearly see the foreground as well as scenery (like mountains and clouds) in the distance. In this situation, you want the viewer to look around the photo, admiring the sweeping view of the landscape. Both of these photographic options are achieved through the technique called ‘depth of field’.
One of the main ways to change your depth of field is to adjust the aperture setting. You can easily do this when using ‘aperture priority’ mode. On Canon cameras it is known as ‘aperture value’ mode. When you instinctively know how to change your depth of field, you can turn a mediocre image into a work of art. The aperture controls the amount of light entering the lens. Wider apertures produce a narrower depth of field range.
The best way to understand this is to try an experiment and see the results you can achieve with your camera. All it takes is a few minutes and a few bottles of wine. Stand the wine in a row and step back a few paces so you are not too close to them. Set your camera to aperture priority mode, and select a wide aperture setting such as f/2. In the aperture priority mode the camera will adjust the shutter speed to get the correct exposure. Focus the camera on the middle bottle and take a photo. Change the aperture to f/8 and take another photo from the same position. Now change the aperture to f/22 and take another shot. It’s time to download those photos to your computer so you can compare the results!
This experiment doesn’t take long, and you’ll have an excellent visual lesson on how changing the aperture creates a variety of depth of field in your photographs. The final step in this process is to open one of those bottles of wine and sip a glass or two while you look at the test shots on your computer, and while you consider how easy it will be to create beautiful portraits and stunning landscape shots simply by adjusting the depth of field of each situation through aperture priority mode.