Depth of field (DoF) is one of the most important concepts for a beginning photographer to understand. When used properly, it can mean the difference between a basic snapshot and a beautiful artistic photograph.
This article will dive deep into depth of field. We’ll explain what it is, why you should use it, and what factors control it. Finally, you’ll learn how to use depth of field to improve your own photography.
What is depth of field?
The depth of field definition is basically the distance between the closest and farthest objects in a photograph that appears acceptably sharp and in focus. Technically, your camera can only focus on a single point in an image. But, the transition from that sharp point to the unfocused areas of your image is a gradual one. The depth of field will determine just how gradual it is and how much of your scene from front to back appears to be in focus.
Deep and shallow depth of field
When we talk about depth of field, we describe it in terms of either deep or shallow.
Deep DoF, also called wide or large depth of field, refers to images in which a large part of the photo is in focus. Landscape photography most often uses a deep DoF. They are in focus from the foreground all the way to the farthest objects in the distance. For more information on how to ensure your entire scene is in focus, check out our guide on how to determine your hyperfocal distance.
On the contrary, a photo with a shallow DoF has an object in sharp focus, but objects in the background (and often in the foreground, too) are out of focus and blurry. Portraits, macro photographs, and wildlife photography are often shot with a shallow DoF. They have soft, blurred, out-of-focus backgrounds that direct the viewer’s attention directly onto the subject of the photo.
Why use depth of field in photography?
You can use depth of field to draw the viewer’s eye where you want it. For example, a shallow depth of field will blur out distracting backgrounds that aren’t a necessary part of the story you’re trying to tell.
What affects depth of field?
There are several factors that affect the DoF of your image: Aperture, subject-camera distance, the focal length of your lens, and the size of your camera’s sensor. Learn how each of these works to change the depth of field and you’ll be able to drastically improve your skills as a photographer.
Many photographers believe this is the only way to control the depth of field. It’s not the only way, but it is probably the easiest. Generally speaking, the wider your aperture, the shallower your DoF. If you want a deep DoF, narrow your aperture.
However, remember that changing your aperture also changes the amount of light that enters your camera, so you’ll need to adjust your exposure settings by changing your shutter speed or ISO to compensate.
Subject’s distance from the camera
The closer you and your camera are to your subject, the shallower the depth of field will be. This is especially apparent in macro photography, which often has a tiny sliver of a DoF, despite shooting with narrow apertures.
Another factor that can have an effect on the DoF of your photographs if the focal length of your lens. Longer focal length telephoto lenses have a shallower depth of field than shorter, wide-angle lenses. This is another reason wide-angle lenses are better for landscapes and telephoto lenses are preferred for portraits.
While it’s not an adjustment you can use to control your depth of field (unless you swap camera bodies), it should be noted that your camera’s sensor size also affects DoF. If all other factors are the same, cameras with larger sensors will have a shallower depth of field.
How to control depth of field in your photographs
To summarize the information above, you can control the depth of field in your photographs by easily adjusting your aperture, the distance to your subject, or your lens’s focal length. This is important to know how to do for different shooting scenarios as you may want a different DoF depending on what you’re shooting. For example, you may find that you’re photographing a family portrait and want a shallow depth of field with a blurred background but need to increase the DoF slightly to allow for the entire family to be in focus.
To decrease DoF for a photo with a soft, out-of-focus, blurry background:
- Shoot with a wider aperture by decreasing your f-number;
- Move closer to your subject;
- Lengthen the focal length of your lens.
In contrast, you can increase the depth of field by doing one or more of the following:
- Narrow your aperture by increasing the f-number;
- Shoot farther away from your subject;
- Shorten the focal length of your lens.
Understanding what affects depth of field and learning how to control it probably makes the biggest difference between people who “just take pictures” and photographers who have creative control over their art. The best way to learn is to just get out and start practicing! Take a photo, change the aperture, and retake the photo. See the difference? Now try the same thing with different focal lengths and by changing your distance from your subject. Practice makes perfect. The more you know, the better your photographs will be.