10/07/2009

Induced Blur

There are times when blur in your images can be really useful.
We have discussed in other chapters, blurring the background to enhance our subject or to disguise any unwanted background elements, such as bright spots, intrusions or other distractions. Working with slow shutter speeds you can also induce blur to create a sense of movement. As with “light trails”.
For example, in broad daylight, inner city street scenes of crowds walking to the subway or traffic stopped at an intersection, whilst other vehicles are speeding away or a train pulling away from the station or subway.
To achieve these effects, a good sturdy tripod is really quite essential, because of the slow shutter speeds you are working with. I would also recommend a cable release. And because we are working in broad daylight, you may have difficulty in getting down to your required speed, as slow shutter speeds mean wider apertures which means more light is getting in to the lens.
If you can operate your camera manually, it is best set to “Shutter Priority” and whatever it is you are shooting will determine the speed at which you set it.
There are three main factors to take into consideration: the speed or rate at which your subject is moving, how much blur you want to give and how much light you have at the scene, because obviously, a person who is walking or even jogging is moving much slower than a bus or train and if you photograph the moving vehicle the pedestrian may totally disappear from view. So you need to find a happy medium there.
It is with this type of photography that the Neutral Density filter will really come in handy. They allow you to get down in speed, come in various densities and will not alter the colours in your scene. Also “Grey Grads” are handy for street scenes where one side of the street is in bright sunshine and the other is in shadow. As Grads (graduated shading), they are shaded at one end, then feather off to clear at the other.
A polariser will also drop your speed by a couple of stops, but will probably not be enough in bright sunshine.
A good versatile lens is all you really need for this sort of work. A zoom lens in the order of about 28 - 200mm will do the job admirably.
So, if your kit fit’s the bill, before you go rushing off to the big smoke, may I suggest that first you get in some practice a little closer to home. This will ensure your confidence for the task ahead.