Bokeh is the word for those defocused discs of light you see in the background of photographs or more generally the pleasing quality of any unfocused areas of the picture. Sometimes these are large circles of colour, sometimes a more blurred mass of smaller high lights.
The term comes from the Japanese word boke or meaning haze or blur.
In practical terms you need to get close to your ‘foreground subject’ and place some bright lights in the medium to far distance. Get so close that you use the minimum focusing distance of your lens – usually about 30cm to around 120cm depending on the focal length. Select your maximum aperture – f/2 or f3.5 for instance. When you take a photo you should find the background lights are extremely defocused. If you are using a zoom type lens your maximum aperture will be limited. If you are lucky enough to be using a prime lens then your aperture should reach f/1.8, f/1.4 or even f/1.2. At these apertures depth of field will be extremely shallow and bokeh effects will be created very easily.
Given that I am writing this during the Christmas season, now is an ideal time to try out bokeh effects. All the flashing and sparkling lights around us are great subject matter and they make great seasonal cards. Give it a try!