As a photographer, I am particularly fond of a shallow depth of field. It’s dreamy, romantic, and semi-abstract. It isn’t exactly what the eye sees – unless that eye is really near-sighted – and the shallower the focus, the more abstract the resulting image. It works in both natural light and when using a flash.
A shallow depth of field is accomplished by opening the camera’s aperture. The lower the aperture number – 4.5, for example – the wider the aperture and, therefore, the smaller the depth of field.
Because the aperture is open wide, your exposure time will be relatively fast in low light and super-fast in bright light. This is something to consider when photographing, say, a butterfly on a bright yellow flower in full sunlight. In order to get that shallow depth of field you want, you may have to lower your ISO or make your aperture smaller in order to avoid over-exposure. (In that particular situation, I might actually prefer more detail.)
A shallow depth of field is generally used for close-up shots. For a landscape or a group of people, a small depth of field will result in much of the scene being blurry. Basically one portion of the photo will be sharp, and the rest will fade into a fuzzy background or even into an indistinguishable blur.
According to Wikipedia, “bokeh” is “the aesthetic character of the area that is out of focus.” If you were to take a photograph of a lit Christmas tree, using a shallow depth of field and focusing on a single ornament, the out-of-focus lights – and reflected light – on the rest of the tree should create a pleasing bokeh (depending upon your lens).
Once you understand depth of field and bokeh – and shut off your camera’s automatic focus – you can really start to have fun creating photographs that don’t look like photographs at all. You can choose to focus on one little area – not necessarily that which is front and center – and let the rest bend and blur into shapes that look like smudges or brush strokes.
