Bokeh means the blur, or the quality of the blur, in parts of your image that are out of focus.
And you can use this to effect. For instance when shooting city lights, or Christmas tree lights, you can make them into circles by throwing them out of focus:
That was shot with a Digital Rebel with a 50mm f/1.8 lens. You cannot get simpler than that!
I tried doing that with mine and you can clearly see the 5 aperture blades on the blurry lights. How did you get them nice and round?
A-ha! If you see a hexagon, your aperture is part closed – that is the shape of the shutter blades.So – open the aperture all the way. Then you get a nice round shape.
So if you have an f/2.8 lens, say, then set the aperture to f/2.8 (in A/Av mode), and Bb’s yur uncle.
I just got a 50mm lens that opens to 1.8 – fun for bokeh shots! I had some fun with it and cut out hearts etc. http://martinsoler.com/2010/06/03/bokeh-love-hearts-candles/
Love in a cup.