I’m often asked about bokeh (which has a myriad of pronunciations bo?k? / boh-kay / boh-k?). The word originates from the Japanese word boke, which means “blur” or “haze.” It is essentially the aesthetic quality of the blur in an out of focus area of a photo. This is generally done to create a pleasant framing for a subject where the background is thrown out of focus and the subject becomes more pronounced.
The goal is to create a background that is pleasing. The goal is to push the scene far enough so that the distracting elements are removed. Bokeh usually appears in the brighter areas of a scene that fall outside of the region that is in focus. However, bokeh can appear at all tonal values.
The easiest way to create bokeh is to use a fast lens. That’s to say one that is capable of shooting at a wide Aperture. The following images were shot in Aperture priority mode under sunlight. The ISO was constant at 160, while the shutter speed varied to balance the exposure.
This first image was shot at /22. This aperture lets in the least amount of light and creates the deepest depth of field. The majority of the photo is on focus and it is a bit hard to know where to look.
The next shot is at /6.3. This is a common aperture found on many kit lenses included with cameras. In this case, the background is softened and its easier to tell what the subject of the photo is.
Using a faster lens means that you can open it up even more. In this case an aperture of /3.2 clearly throws the background out of focus. However the backside of the flower also becomes soft. This would be the maximum I would open up the lens for this shot as the primary subject is starting to lose definition.
This is the widest open my 50mm lens could go. This is the 50mm /1.8 (often called a nifty fifty). You can also find more expensive lenses that go as fast as /1.2. In this case the subject has focus problems as too much of the flower is out of focus. It is about 10 inches in diameter and the shallow depth of field made it impossible to keep the entire subject in focus.
When it comes to bokeh, the right amount is very subjective. Always try to balance how important the background is to your foreground. For the lizard, I wanted to preserve the background but still balance the image. The parrot was at a busy farmer’s market, so the background was unrelated to my subject. The Palm Springs cactus was subjective, but I pushed things pretty shallow. Be sure to experiment with your lens collection… remember the easiest way to experiment is using an Aperture Priority shooting mode.