A beginner’s guide to action photography
5 07 2008Many thanks to Canon…
If only everything stayed still, photography would be so much simpler. We can take our time photographing a building, or a landscape. Neither is going anywhere. But the moment you start shooting action, you introduce a whole new set of problems.
Action photography is not just about sports. An excited child or animal are just as difficult to photograph. Not only do you have to keep the subject centred in your camera, but you also have to avoid it appearing as an unrecognisable blur.
The problem is that the image of an active subject can move across the digital sensor of your camera during the exposure. In effect, a whole series of images of the subject is recorded, each merging into the next. The result is called blur. Even a relatively short exposure time can lead to significant blur if the subject is moving fast.

One way to overcome blur is to use a shorter exposure time. If the image has less time to move across the sensor, the blur will be reduced and you will eventually reach a point where the image appears sharp in the photograph.
Shutter speeds
The exposure time in a camera is controlled by a shutter. It opens and closes to control the duration of the light reaching the sensor. The time open is called the shutter speed. On digital cameras, the image is captured by turning the digital sensor on for a very brief period of time.
Typical shutter speeds on cameras are 1/60 second, 1/125 second and 1/250 second. These are very brief durations but not brief enough to eliminate blur from some moving subjects. So what shutter speed do you need?
It all depends on how fast the subject is moving, its distance from the camera, the direction the subject is moving relative to the camera, and the focal length setting of the lens.
A subject moving parallel to the image plane – that is, from one side of the frame to the other – needs a faster shutter speed than a subject moving at the same speed towards the camera, because the movement is more apparent. A subject moving diagonally towards or away from the camera falls between the two.
The further you are from a subject, the slower it will appear to be moving. Think of an airliner high in the sky. Although it is moving at hundreds of miles an hour, from the ground it appears almost stationary.
With digital cameras, you get instant feedback in the form of the preview image. Is a moving subject sharp in the image? No? Then set a faster shutter speed and shoot again.
It is possible to display a magnified view of part of the image you have just taken. This gives a much better idea of whether or not the subject appears sharp.
ISO speeds
The shutter speed is only one factor affecting the exposure of an image. Another is the lens aperture. This controls the brightness of the light reaching the sensor. If you alter the shutter speed, the aperture may need to change to maintain the same exposure. A slow shutter speed with a small lens aperture can give the same overall exposure as a fast shutter speed and a wide lens aperture.
Most of the time you do not need to worry about this. The exposure system of your camera will automatically alter the aperture if you change the shutter speed.
However, in low light, there will come a point where the aperture is at its widest setting. Continuing to set faster shutter speeds at this point will lead to underexposed images. One way to overcome this is to set a higher ISO speed. In effect, this increases the sensitivity of the digital sensor, allowing correct exposure in lower light.
The disadvantage of higher ISO settings is a lower image quality. However, Canon cameras are very good at holding quality at the higher ISO settings, so it is well worth shooting at ISO 800, or even 1600 (if available on your camera), if the light is too low for photography at ISO 200 or 400.
Panning your camera
There is another technique for obtaining sharp images of moving subjects – one which can be used with relatively slow shutter speeds. It is called ‘camera panning’. All you have to do is move the camera to follow the subject. The idea is to keep the subject stationary in the viewfinder. This will give a much sharper image of the subject than keeping the camera still. At the same time, moving the camera will blur the background, giving added emphasis to the sharp subject.
Panning the camera smoothly, and at the right speed for the subject, takes practice. This is easy with a digital camera, as there are no film or processing costs associated with the exposure, and you can see the results immediately. You can go along to a local sports meeting - athletics, cycling or motor racing - to practice your panning technique.
Sports mode
By their very nature, action photos often don’t allow you the time to prepare or select the best settings. To help you with this, many Canon cameras offer a ‘sports’ or ‘action’ shooting mode. This mode selects a fast shutter speed to ‘freeze’ the action of your moving subject. It may not be exactly right for that situation but it does mean that you can be sure you get a shot.
Comments : No Comments »
Tags : action, blur, Exposure, panning, photography, shutter, sport
Categories : Canon, Exposure, Getting Started, Motorsports, Photo Tips, Shutter Speed, Techniques



















