As photographers, depth of field is something that’s important to take into account with every image we produce. While it can create some cool creative effects like bokeh, it can also be used in professional ways to create a more appealing photograph.
What is depth of field?
Simply put, depth of field is the “distance between the nearest and farthest objects in a scene that appears acceptably sharp in an image” (Wikipedia). A large, or broad, depth of field (small opening large number i.e. f/16) has more of the image sharp and in-focus, while a small, or shallow, depth of field (large opening small number i.e. f/2.0) has less of the image sharp and in-focus.
When to use a shallow depth of field
While you want your images to be in-focus and sharp, it’s also important to put an emphasis on your subject. Using a shallow depth of field can help to isolate your subject from what’s behind. This technique is useful in things like environmental portraits, nature, sports and editorial photography.
Using a shallow depth of field can also create the effect known as bokeh, which occurs when you have a shallow depth of field and small light sources behind your subject.
When to use a broad depth of field
When you’re photographing a subject that has to be fully sharp, you’ll want to increase the depth of field. This can be particularly useful with landscape, architecture and product photography, but it can also mean that your background will compete with your primary subject for attention in the photograph.
How to control depth of field
Control depth of field by adjusting your aperture. By using a small f-stop number (and therefore opening up your lens), you create a shallow depth of field that blurs the background.
Alternatively, by using a large f-stop number (closing your lens), you create a broader depth of field, sharpening your image across the frame.
But playing around with your aperture dial isn’t the only thing that will control your depth of field — the distance between your camera and subject also effects depth of field. The closer you move to your subject, the more blurry your background will appear, and the focus point will get smaller. The further away you move, the larger your focus point gets, and the sharper your image gets.
If you can’t change your physical distance, try changing the focal length of your lens instead. The longer you go, the more shallow depth of field you’ll obtain.