Light, camera, action

A moving subject presents the photographer with a situation that requires quick thinking and plenty of preparation. Photographers don’t capture images of rapidly moving subjects such as lions chasing prey by merely reacting to what passes in front of their eyes. They come prepared for the confrontation and are able to anticipate the speed of the action and direction of travel.

Before you pick up your camera, you need to decide in advance whether to freeze the action with a fast shutter speed or emphasise the movement through techniques such as panning, slow-sync flash and time exposures. Your decision will depend largely on the subject and setting, as well as any technical limitations of your equipment.

One of the basics of photography is learning which shutter speed to choose with the lens in use in order to achieve a sharp image unaffected by the dreaded ‘camera shake’. There is an old rule of thumb for the 35-millimetre format that the minimum shutter speed selected should be the equivalent to the focal length of the lens in use, so 1/30sec for a 28-millimetre wide-angle lens, all the way up to 1/500sec for a 500-millimetre telephoto.

Although digital imaging means we can now work with a different range of focal lengths and with a greater choice of shutter speeds, the principle of this rule remains the same. Simply, the slower the shutter speed, the greater the chance of there being unwanted image blur or movement in your pictures. Unless, of course, you actually want to record such image blur. In that case, combining slow shutter speeds with panning proves most effective.

Action panning

Many wildlife and sports photographers use panning to depict a rapidly moving subject against a blurred background in order to convey the speed of the action and concentrate more of the viewer’s attention onto the subject. Panning is best executed when the camera locks focus on the subject and follows its path in a steady sweep, even after the shutter has fired. The camera’s autofocus needs to be set to continuous (predictive) AF mode and the shutter speed slow enough (1/60sec or less) to render the background as a streaky blur while the moving subject stays relatively sharp. This technique is effective with many wildlife images as well as sporting and cultural events.

The effect can be further accentuated by the use of flash. Most SLR cameras have a flash sync speed of 1/125sec or 1/250sec. (Remember, the flash sync speed is also the maximum shutter speed you should use with flash.) Using a slower shutter speed allows the scene to be recorded with the ambient light as well as the light from the flash. The effect of the ambient light on the scene, particularly the background, increases the longer the shutter stays open. If you’re close enough to the subject, the flash will help fill in any shadows and render a ghosting effect on moving parts.

When taking photos while panning, just focus on your subject–for example, a passing cyclist–and keep it within the frame, tracking its path across you. With your camera’s motordrive set to continuous, a burst of flash exposures with the shutter set at say 1/30sec will produce a well-lit foreground and focused target, but with a streaked background that helps emphasise the speed of the bicycle. By checking your results on the monitor you can determine if your choice of shutter speed was best for the desired effect.

Wildlife and water

Of course, not all subjects move as predictably as a passing cyclist. Wildlife, especially birds in flight, can be more unpredictable, and it pays to spend time observing the habits of your target. Knowing where a bird is likely to perch will help enormously in your attempts to photograph it in flight, as the instant before landing is when a bird’s flight is at its slowest.

Landscape photographers use shutter speeds of several seconds, even longer, when photographing scenes of moving water such as a waterfall or the sea rising and ebbing on the shoreline. Such slow shutter speeds (time exposures) create a soft and misty impression of water, erasing any defining lines of shape and depicting the surface as a study of muted colour. However, to be fully effective, the camera must be fixed on a tripod and the shutter released by a remote release or self-timer.

Freezing action

Freezing high-speed action requires a different approach. The quicker the subject, the faster the shutter speed required. Assuming there is enough light to ensure an accurate exposure, a shutter speed of 1/500sec will be adequate for most lenses and in most situations. Subjects such as F1 racing cars, skiers and other sports action will require something faster.

Stopping down the lens to its maximum aperture will give you the best chance of using the fastest possible shutter speed. Fast shutter speeds lessen the risk of camera shake, but some form of support, such as a tripod, is still advisable.

When photographing ball games, you will need to fire a continuous burst of frames to capture the moment when ball meets racquet, bat, boot or club. Even then, it will be mostly luck that determines if you’re successful.

Dos and don’ts of photographing moving subjects

Do …

* When panning, make sure to keep your camera moving evenly before, during and after firing the shutter

* Switch your camera’s autofocus mode to ‘continuous’ Many cameras now have a sophisticated ‘predictive’ algorithm that keeps up with changes of speed and direction as long as the subject is tracked

* Consider a monopod over a tripod. They are quicker to set up, keep your camera steady while panning and won’t get in anyone’s way

Don’t …

* Use a shutter speed faster than your camera’s flash sync speed if using flash. If you do, part of your image will be blacked-out by the shutter blind passing across the image sensor during exposure

* Forget to check the maximum range of your flash. Flash falls off quickly and less light may reach your subject than you think

* Just shoot from the hip, particularly when using long lenses. Always consider some means of support, even a beanbag on a ledge or car window sill

Equipment: lenses and cameras

Lens options: lenses to heat the shakes

Canon was the first manufacturer to develop special lens technology to counteract lateral and vertical movements caused by hand holding. Its range of image stabilising lenses make it possible to use slower shutter speeds for sharp results when using a camera and lens without a tripod. Nikon has a similar range of vibration reduction lenses, most recently applied to a 105-millimetre macro, while independent lens maker Sigma has developed an optical stabiliser lens range covering some telephoto focal lengths. While these lenses can’t substitute for the complete stability of a tripod, they can be a limited alternative in situations where a tripod is impractical.

Contacts: www.sigma-imaging-uk.com, www.canon.co.uk, www.nikon.co.uk

Digital option: Sony a100

Sony’s first interchangeable-lens digital SLR costs just 599 [pounds sterling] body only and is fully compatible with the Konica Minolta range of 35-millimetre and digital lenses. This camera features Super SteadyShot, a system that compensates for body vibrations at the instant the shutter is released by tilting the CCD image sensor in real time for sharper pictures. Because it is built into the camera, Super SteadyShot works with all Sony [alpha]-mount compatible lenses, thereby saving the need to buy into a specialist lens range.

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