Achieving bokeh in your images
To achieve bokeh in an image, you need to use a fast lens—the faster the better. You’ll want to use a lens with at least an f/2.8 aperture, with faster apertures of f/2, f/1.8, or f/1.4 being ideal. Many photographers like to use fast prime lenses when shooting photographs that they want visible bokeh in.
You’ll want to shoot with the lens wide open, so it's best to use Aperture Priority or Manual shooting modes. Manual gives you the ability to choose both your aperture and shutter speed. Aperture Priority allows you to choose the f/stop (aperture) while the camera chooses the appropriate shutter speed for the exposure. You could also use the Flexible Program mode, which will let you choose the widest possible aperture/shutter speed combination.
Don't worry if you don't own a very fast lens. By increasing the distance between the background and your subject, you can see bokeh in images that are shot at smaller apertures.
To increase the likelihood of visible bokeh in your photographs, increase the distance between your subject and the background. You can do this by decreasing the distance between the camera and subject. The more shallow the depth of field, or the further away the background is, the more out of focus it will be. Highlights hitting the background will show more visible bokeh too. If you’re using a backlight, side light, or hair light, the bokeh may be more pleasing to the eye.
Portraits are excellent for bokeh. Close-up portraits in particular show bokeh very well. Close-up and macro images of flowers and other objects in nature are also popular subjects for showing bokeh. And a grouping of holiday lights or other highly reflective objects, purposely photographed out of focus, become diffused orbs of glowing light.
Bokeh can add softness to an otherwise brightly lit photograph. Using this technique to separate your subject from the background can also allow you to utilise a not-so-photogenic backdrop. Because of its diffused blur, it helps to highlight the subject instead of detracting from it.
Article and imagery contributed by Jody Dole, Kristina Kurtzke, Lindsay Silverman, and Paul Van Allen