What is Bokeh and how do I photograph it?

In photography “Bokeh” describes the blurring or hazing effect that is created in the background of your image while retaining focus on a foreground object. Many people try to achieve this effect without success or do so haphazardly. There is a common misconception that you need a long zoom lens to achieve this, but I will attempt to explain how you can get this with any lens, including you kit lens.

The basic guide to achieving the Bokeh effect relies on 3 guidelines:

  1. Take the focal length you have set your lens to, such as 50mm, then add a zero to get 500mm. This is then a good distance to be from your subject to get good background bokeh.
  2. Your subject should be 10 times the distance you are from them away from any background. So let assume you have set your 18-55mm kit lens to 50mm, you stand 500mm (1/2 a meter) away from the subject you want to photograph and the background is 5000mm (5 meters) away, you can expect a good bokeh.
  3. Your aperture should be as wide open as possible (Aperture should be set to the smallest number it will go.) It is therefore preferred that you set your camera to Aperture Mode (A or Av) and turn the dial to get the smallest number (widens the aperture). The shutter speed should take care of itself.

Now using the above snap your shot and you should find the background nicely out of focus. Remember that once you move 20x your lens focal length away from your subject (on 50mm this would be 1 meter) the bokeh effect will rapidly fall away. There is another popular misconception that a prime lens such as a 50mm F1.7 will always creates bokeh, but this is not entirely true. A 50mm f1.7 at 1 meter from a subject does create more blur/bokeh, but the effect is essentially lost.

Though prime lenses are suggested they are not always required to achieve good bokeh. Here are a few samples using different lenses so you can see the effect.

28-75SAM at 50mm at f2.8The photo on the right was shot with a SONY 28-75mm SAM lens at f2.8 at 50mm, 500mm from the flower.

This lens creates beautiful bokeh circles and strike an nice balance between background saturation and contrast. This is my favourite lens for weddings and studio shots. This lens is on my SONY A55 camera 90% of the time.

You can still see some of the background, but the bokeh is just enough to make it look soft.

50mm Prime f1.7The photo on the left was shot with a 50mm Minolta f1.7 Prime (fixed focal) lens.

At 50mm with f1.7 it creates huge bokeh circles with a very soft look. The colour saturation and contrast is very similar to the SONY 28-75 f2.8 SAM lens.

I prefer to use this lens in low light situations and it is usually fitted to my SONY a230 Camera. During those preparation shots with brides it provides a nice blur of the background in low-light situations.

18-55mm Kit at 50mm with f5.6The photo to the right was shot with the SONY 18-55SAM kit lens set at 50mm and F5.6 (the one the usually ships with a SONY camera). You will notice the bokeh has an odd shape to it and is much smaller than with the above lenses. The background is also much less saturated with less contrast. Though this is not a bad lens, I hardly every use it and it is kept in my case only as a spare.

This lens is a good all-rounder, but when you get into specific situations, especially low light, then lens shows its weaknesses. This lens is very similar to those NIKON and CANON camera ship with. These lenses are referred to as Kit lenses and are considered “beginner” lenses and not appropriate for any kind of professional shooting.

75-300SAL_50mm_f5.6To the right is a shot using a SONY SAL 75-300mm lens at 300mm and F5.6. There is a belief that by some that Bokeh can only be achieve with a strong zoom lens, but the effect is more of a deep blur than an appealing bokeh. Though this still qualifies as bokeh the blur desaturates the background and messes up the contrast so much that it doesn’t appeal to me. But, if this is all you have to work with then you use it! (There was a time that this was all I had)

In this case I stood about 3 meters from the flower to get the approximate same frame. Again this conforms to my general guide of 300mm x10 as a good distance to from the subject to get good bokeh. With zoom lenses you get way different light divergence which is a subject all on its own and will not get into here.

19-35mmTokina_35mm_f4.5On the right is a photo shot with a Tokina 19-35mm lens at 35mm (350mm from flower) at f4.5

This is a very old type lens, but it has replace my kit lens completely. It has a smaller, but perfect bokeh which is very appealing. The 35mm also gives you more background to work with which does make it a little busier than longer focal length lenses, but this is desirable in many cases. This lens is a stunning outdoor and landscape lens and I wouldn’t normally use it to achieve bokeh. The photo is here just as an example to show that bokeh can be achieved with any lens at its widest aperture.

Note that as you close your aperture (bigger f number) your depth of field (DOF) increases and the background will come more into focus losing your bokeh. Achieving a nice bokeh with your camera in “Auto” (green mode) mode is rare as most cameras will average between the aperture and shutter to balance the exposure. This usually results in a larger smaller aperture which usually kills bokeh. Learn to take you camera out of “Auto” mode and look into using the “Aperture” mode more often.

I hope the above explanation and guides help you find your bokeh!



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