Depth of Field - How To Take Portrait Photos with Blurry Background

Portrait photos give us memories of the best moments of our lives. In order to have a good portrait photo, the depth of field and its control plays a key role. Controlling the depth of field (DOF) is accomplished by adjusting your aperture setting (the size of your lens opening, expressed in f-stops). The smaller the f-stop the larger the opening of your lens, and the smaller the depth of field will be.

For instance, when you see a photograph in a nature magazine of a beautiful butterfly in a patch of flowers, and the butterfly is in razor sharp focus but the flowers are gently blurred; this was accomplished by the photographer using a narrow depth of field (small f-stop setting). For bright light situations this may be difficult to achieve. For any given intensity of light, as you open up the aperture (lower the f-stop) you must increase the shutter speed (thereby decreasing exposure time) to avoid over exposure. Increasing the shutter speed generally reduces resolution in the image. Experiment to find the combination of aperture setting and shutter speed that gives the result you desire.

Control the depth of field (the range of distances from your camera that are in focus). The edge of a forest, or mountains in the distance may render beautifully as a backdrop for your subject with proper control over the depth of field. If you have an SLR camera, you can adjust your depth of field to bring the background more or less out of focus relative to your subject. This serves as eye control for the observer of your portrait. The eye is naturally drawn to what is brightest and most sharply focused. If your subject is sharply focused relative to the background, she will be accentuated as the focal point of your portrait.

How do you control the depth of field? Depth of field is an optical figure that is influenced by a few factors:

1. The distance of the object from the camera
This is obvious to understand when taken to the extreme. Shooting an object 10 feet from the camera will result in a smaller depth of field than shooting an object 100 feet from the camera. Obviously shooting an object which for all practical purpose is infinite distance from the camera will result in the camera focused on infinity and the depth of field being infinite too.

2. The aperture
The wider the aperture (f number decreases) the smaller the depth of field and vice versa: the narrower the aperture (f number increases) the greater the depth of field. Just remember that the depth of field changes along with the f number: when the f number increases and depth of field increases and vice versa. Unfortunately you can not just change the aperture as you wish. Changing the aperture results in a need to change the shutter speed (either manually or the camera can most likely do that for you automatically). The wider the aperture the more light that penetrates the lens and the faster the shutter speed needs to be so there is a limit to how wide you can set the aperture to.

3. The focal length of the lens
The shorter the focal length the greater the depth of field and vice versa the longer the focal length the smaller the depth of field. For example if you use normal lenses at somewhere around 50mm your depth of field will be much greater than if you use zoom lenses at 200mm. With long focal length the depth of field can be extremely small. For that reason zoom lenses are a good choice in order to shoot a good blurry photo that is practically focused only on the object.

After understanding the theory it is best to go to the field an experiment. You will get a sense of how your photo will look like and how blurry the background will be after playing with different lenses, different apertures and different distances from your object. If you own zoom lenses start with taking photos of a relatively close object while using your zoom lenses. You will find out that it is extremely easy to get a blurry background photo using this method even without setting the aperture. Once you feel comfortable with that setup start changing the aperture and also change to your normal 18mm-55mm or similar lenses.

Keeping your composition simple, controlling the depth of field, and eliminating objects that may distract from your subject, all help to accentuate your subject as the focal point of your portrait. Controlling the available natural light and correcting the white balance of your photographs can reveal and enhance the true beauty of your subject. Beyond this, make it your aim each day to unleash your creativity that you may see the world around you in fresh and unique ways. Never be content with seeing the ordinary as ordinary. Just stop and think for a moment, everything there is, is ordinary to someone. Art is created by those with the ability to see beyond the ordinary, to interpret their world in an exceptional way, and to reflect their interpretation for others to see. So, experiment and don't be afraid to try something new. The world is abundant in forms, textures, colors, and patterns of light. Grand landscapes and magnificent manmade structures are not required for great photos in the great outdoors. May Mother Nature always cooperate with you.