As this photo shows, using a shallow depth of field (DOF) for portraits emphasizes your subject. A viewer’s eyes are automatically drawn to the only thing in the photo that is in focus.
The term “depth of field” means the range of distance from your camera within which your photo will be in acceptable sharpness. So what we are shooting for here is a DOF that has your subject in sharp focus but the foreground (if any) and background out of focus.
How To Get Shallow Depth Of Field
There are three main ways to get a shallow DOF . . .
- Large aperture. Set your shooting mode to aperture priority (or manual) and set a large aperture. Don’t forget, the smaller aperture numbers (f-stops) are actually larger lens openings. To remember this, for years I have repeated this mantra to myself: “small number, small depth of field.”
- Long focal length lens. Shorter focal length lenses will increase the DOF and longer focal lengths will decrease it. So for a shallow DOF, use a “long lens.” If, for examaple, you have a 70-200mm zoom lens on your camera, you will find that the same subject shot from the same place with the lens zoomed to 200mm lens will have a shallower DOF than you will get when you shoot at 70mm.
- Shorter focusing distance. The shorter the distance between your camera and your subject, the shorter your DOF will be.
Actually, I can think of two other factors that affect DOF.
One is the distance from your subject to the background. The farther the background is away from your subject, the more likely it will be out of focus.
In addition, larger camera sensors can produce shallower DOF. A full-frame DLSR, for example, is capable of producing a shallower DOF than a phone camera, a point and shoot camera and even a crop-frame sensor DSLR camera. Of course, the full frame cameras cost more, too.
Tips For Using Shallow Depth Of Field
If you are shooting a portrait of more than one person, keep them all on the same plane. What I mean is, keep them all on an imaginary line that is parallel to your camera body. If, for example, you have subjects in a moon-shaped semi-circle and you focus on the center person while shooting for a shallow DOF, the subjects on the sides, who are closer to the camera, will be less sharp than the person in the center on whom you are focusing.
This same technique of emphasizing your subject by using shallow DOF also works great in macro (close-up) photography, flower photography and sports photography.
To get a deep DOF, you basically reverse this procedure, but I will cover the details of that in a later Beginner Photo Tip.