A long exposure is a great way to inject motion and drama into your shots.
You’ll need a tripod to completely lock off the camera. Then anything that is moving in the frame, such as the sky, water or even people, will be turned into an artistic blur. Stationary subjects such as buildings will remain pin-sharp, adding contrast to your blurred subject.
To get started you need to find a scene with a mixture of stationary subjects and movement. Waterfalls, beaches and landscapes with moving clouds are just a few examples of the type of scenario that lends itself to a long exposure. On beaches, if your tripod has spiked feet then use them, as this will give it extra bite on wet rocks. I would stay away from using your tripod in the sand as it could sink a little during the exposure, which would lead to a blurry shot.
Now you need to frame up and compose. Make sure you take into consideration where the moving subject will be going, as this can be used creatively in the framing to lead the eye through the picture. In terms of lenses and focal length, there’s no right or wrong choice. I’ve taken great wide and zoomed-in shots, each with their own sense of scale. Try to take a couple of the same scene with different focal lengths so you have a few options to choose from back at your computer screen.
When you’ve framed up, place your active AF point over a stationary object that’s about one-third of the way in to the shot – this will give you the best chance of rendering the whole shot in sharp focus. When you’ve set the focus, switch your camera or lens to manual focus to lock it off.
Go into your camera’s aperture-priority mode and set the lowest ISO value (usually 100) and the highest aperture value (f/22 on many kit lenses). This will give you the longest possible exposure, and probably result in a 1sec or 2sec exposure in modest light. Engage the 2sec self-timer to reduce the chance of camera shake and take the shot. Then check it on your camera’s LCD to see if it’s the right amount of blur for you. If there’s too much blur, you can widen the aperture a little and this will give you a slightly faster shutter speed with less motion. On the other hand, if you’d like more motion you’ll need a light reducing neutral density filter.
Using neutral density (ND) filters
Neutral density filters block out some of the light and this allows you to get much slower shutter speeds than normal. They come in different strengths and are labelled by how many stops of light they prevent entering the lens, such as 3-stop or 6-stop. Really strong ones such as a 10-stop (aka Big Stopper) are unlikely to be called an ND. This is because most have a strong blue cast so the colours are not totally neutral. The colours are usually easy to fix in RAW editing software with the Temperature slider. Anyhow, the principle of reducing light is the same as with an ND.
ND filters come in two types – circular screw-in ones, or rectangular plates you need to slot into a filter holder. The circular screw-in types are usually more affordable, though the filter holder method means you can remove the filter quickly to recompose – with a strong ND attached the viewfinder will become almost impossible to see through – so this is a big feature to consider.
The longest shutter speed you can set on most DSLRs is 30sec. This isn’t that long, considering a 10-stop filter may give you an exposure of several minutes. So you’ll need a shutter release cable which lets you lock the shutter button down in Bulb mode, and keep it open for as long as your exposure requires. Most companies provide a chart to help you set the right exposure with the light reduction filter. These charts tell you what shutter speed to set for a correctly exposed image. I printed mine off and taped it to the top of a tripod leg so I always had it to hand.
Dan Mold is a professional travel and wildlife photographer and a regular contributor to Practical Photography and Digital Photo. He has recently returned from an epic adventure around Asia and Australia. See more of his work here.