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. Lets take a look…
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 static subject and a blurred background is a blur of little circles, That is bokeh. It is created by the lens and aperture.
When you use a wide aperture, say f4.0 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 trueness 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 as circular bokeh. Less 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. 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.
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!
This is one of the less well known types of blur. You need a steady hand or better, a tripod. It makes the picture look like the world is rushing toward you very rapidly.
Zoom blur is done by adjusting the zoom during exposure. 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. Set your lens to manual focus. 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. A bit of practice is needed not to hand-shake blur the shot too. A smooth zoom throughout the exposure can create some great effects. Here is a page of zoom blur images on Google .
Most image editors have software filters to create types of blur. There are a whole variety of them. Gaussian blur is one common type. It has a smoothing effect on 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. Different packages 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. Where as blur using depth of field gives depth to a picture. Bokeh blur, or 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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