Not all blur is equal.
There are various types of blur. It sounds odd. In fact there is a lot more to blur than most people realise. It is quite a varied subject. It is used in nearly all aspects of photography. From abstracts to zooming, we will find some aspect of blur. Lets take a look…
Okay bokeh…
First up, and one of the best known types of blur, is Bokeh. This Japanese word means haze or blur. It originally referred to the quality of blur. Today we use it to describe the actual blur. A sharp subject and a blurred background is created by a blur of tiny circles where each of the tiny points of light are not focused, that is bokeh. It is created by the lens and aperture.
When you use a wide aperture, say f4.0 (or wider) you get a shallow depth of field. The depth of field is the sharp part of the picture. The rest, the out-of-focus part, is blurred. That blur is the bokeh.
Bokeh can add a whole range of composition effects. It is also has its own aesthetic quality. The quality of the little ‘circles’ varies as does the true circular shape of the circles themselves. Photographic lenses with apertures that are more circular produce the best bokeh. Some apertures are more like regular polygons (say a hexagonal). Polygon bokeh is not as pleasing to the eye as circular bokeh. Fewer sides on the polygon forms a less circular bokeh circle. It may even form an obvious bokeh polygon. Manufacturers go to some lengths to make the bokeh pleasing. One way to make the bokeh more circular is to add blades to the aperture diaphragm. That can raise the cost of the lens.
Subject-movement types of blur
When a subject moves in front of your stationary camera the resulting image has a blurred subject. This is movement blur. The types of blur which include movement can be varied. In the picture above the motor bikes are moving at around 90 miles per hour. When taking this shot I was panning with the far bike resulting in that bike being sharp. The pan meant that my camera was not paced at the same speed as the nearest bike. As a result its movement was relatively out of synchronisation with my camera. The nearest bike was in relative movement and thus blurred.
In “The Barber”, below, I have set my camera to capture the blur of his working hands. As with any movement shot, you want some of the shot blurred and some sharp. If it is all blurred it just looks badly taken.
• The Barber By Netkonnexion in 365Project •
Click image to view large
The Barber By Netkonnexion in 365Project 
The movement of the hands is blurred to simulate his hair cutting work. Types of blur created in-camera are most effective.
Movement of the subject is controlled by shutter speed. To get it right you have to practice with the speed of that subject. Try the subject at slow speed first. Once you have an idea of the settings, speed the subject up. As you develop a feel for the speed-of-movement versus the shutter-speed you will be able to get a sharp background but a blurred subject.
More types of blur… Camera movement
When a subject is moving pan your camera with it. I did that in the bike picture at the top of the page and got a sharp bike placed against a blurred background. That is not bokeh in the background. As the camera panned with the bike it captured a stationary background. However, as the camera was moving it created a movement blur on the background.
Movement blur of the background normally occurs when panning. If you hold a stationary camera out of a car window and take a long exposure and the same type of blur will result. However, nothing will be sharp in that case (unless something next to you is travelling at your exact speed).
Done right background blur from camera movement has great impact. In the motorbikes above it gives a race feel. It looks really fast.
Some blur is not so good
Hand movement during a shot causes all sorts of blur. You get blurred shadows, blurred faces, possibly jerky tracks… not good at all. However, you can have some fun with this sort of movement. Some famous pictures have been created by deliberate hand movements. There are lots of shots, like tree shots , where the movement of the camera creates a surreal or abstract view of the subject. Some people have tried throwing their camera and triggering it in mid-air – some bizarre results can be obtained (including a smashed camera).
Out of focus types of blur
Of course it is possible to completely blur a shot quite deliberately. Some pleasant aesthetic effects can be achieved. Wedding and romantic photographers love the “soft focus” shot. This is a deliberate very slight lack of sharpness. It emphasizes the romantic, soft nature of something… kittens, brides, the first kiss, baby and so on. Google images of soft focus shots provides quite a good range of possibilities for this type of blur.
The soft focus shot can be created different ways. Each give slightly different types of blur. You can literally set the lens to manual focus. Then when properly focussed pull the focus slightly back. so as to create a small amount of blur. Another way to do it is to use a soft focus filter. These are simply screwed to the end of the lens and give the same effect. When I was first starting out in photography many wedding photographers carried a flesh coloured or white nylon stocking. Pulled tight over the lens while the photograph is taken it creates a soft focus effect. Others like a skylight (ultraviolet) filter with a tiny amount of grease smeared on it. All these work, but give you a slightly different soft focus effect. Experiment… have fun!
Zoom blur
One of the less well known types of blur – zoom blur. You need a steady hand or better, a tripod. It makes the picture look like the world is rushing toward you very rapidly.
Adjusting the zoom during exposure creates zoom blur. Set your camera to have a long exposure – around one second is good. Balance the shutter speed with the ISO and aperture to get a proper exposure. You will need to use manual focus to adjust the zoom in the shot. Press the shutter button and rotate the zoom focus ring. A short turn or through its full arc – the amount of turn gives different effects. With a bit of practice you can reduce hand-shake blur. A smooth zoom throughout the exposure creates some great effects. Look through this page of zoom blur images on Google for some ideas… .
Artificial blur
Most image editors have software filters to create types of blur. In fact there are a variety of different software filtersavailable. Gaussian blur is one common type. It softens or smooths the image, but also causes loss of detail. There is also rotational blur (self explanatory); linear blur or movement blur – you choose the direction of the blur. Other editng packages will have other blur types too.
Artificial types of blur do not have the same effect as blurs created in-camera. Artificial blur tends to lack depth. Whereas, blur using depth of field gives depth to a picture. The bokeh and movement blurs both have the impact of realism and depth as they vary throughout the depth of the image. Applying a uniform artificial blur can affect the realism. Applied with care and artful work you can make artificial blur look real. It is all about care and attention.
Are there more blurs?
There are probably other types of blur. They may fit into one or more of the categories above. Why not let us know about others. I would like to hear of new ideas and types of blur.
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By Damon Guy (author and Photokonnexion editor)
Damon Guy (Netkonnexion)
Damon is a writer-photog and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photographers.
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Editors ‘Bio’.
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