Changing the depth-of-field can have a dramatic effect on a photo. It can isolate a subject and create a beautiful backdrop of blurred shapes and colors or it can do the opposite and reveal the whole scene in perfect clarity. And you, the photographer, are in control of altering the amount of focus in a scene. In fact, there are three main ways to change your depth-of-field:

Aperture

Changing the aperture is the easiest and most common way of altering the depth-of-field. The wider your aperture (smaller the f-number, like f/1.8) the shallower the DoF will be. Likewise, the smaller your aperture (bigger the f-number, like f/22) the more that will be in focus. Most zoom lenses will only have max aperture of around f/4 or f/5.6. Some expensive zooms may even have a max aperture of f/2.8. But prime lenses are your best bet if you want to be able to get that really narrow DoF for beautifully blurred backgrounds. 50mm primes are the most common and typically have a max aperture of f/2.8 to f/0.95. The 2.8-1.4 versions can be very affordable.

Distance From Subject

The distance from you to your subject has a huge impact on the DoF. The closer you are to your subject, the shallower the DoF. The opposite goes for when your subject is far away. So for instance, if you're photographing a mountain range, you will most likely be focusing at infinity and the majority of your scene will be in focus, even if you're shooting with a wide aperture. However, if you're photographing a flower that's only a few inches from you, your DoF will be very narrow even if you're stopped down to f/22.

Focal Length

The focal length of your lens can also affect how much of your scene is in focus. Wide angle lenses will have a greater DoF while telephotos will have a shallower DoF. This means that you can shoot with wide angle lenses with a wide aperture and still have most of your scene in focus.

When to Change your DoF

Not only is it important to know how to change your depth-of-field, but also when to do it. There are plenty of occasions for both shallow and deep DoF. For instance, with landscapes you often want all of your scene in be in focus. You want to see the foreground and background with the same clarity. However, for head shots of people, you often want a shallow depth-of-field so that the background isn't disrupting your subject.

Of course, it ultimately depends on how you want the photo to look. Maybe you want a head-shot of your friend, but you also want to see who or what is in the background. Maybe you found a beautiful mountain range, but you want to focus more on the field of flowers in front of it. How you decide to shoot your photo is up to you. Just don't get stuck always shooting wide open or closed down. Always remember you have the ability to change your depth-of-field.

Also Read: 23 THINGS YOU MUST KNOW TO BE SUCCESSFUL IN PHOTOGRAPHY

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Image credit: shadowchaser / 123RF Stock Photo

Written by Spencer Seastrom