Slowing down your shutter speed so you transform moving subjects into an artistic blur is one of the most exciting ways you can take creative control of your camera’s exposure. Photographers use long exposures to capture truly compelling landscapes, where flowing water is rendered as a smooth and captivating streak, and clouds become poetic smudges.
Shooting with a super slow shutter speed is also favoured by architectural photographers, as any people walking through the frame won’t be recorded in the image, creating a distraction free shot.
Long exposures transform water into a milky blur
The rush of a waterfall makes a great long exposure subject
Even drifting clouds are transformed into artistic smudges in the sky
However when shooting in broad daylight the conditions are far too bright for cameras to shoot with the requisite slow shutter speed. Even by fully stopping down your aperture to its minimum setting – often f/22 – and dialing down the ISO to the lowest sensitivity available your shutter speed will likely linger around the 1 second mark. This isn’t long enough for the most captivating slow shutter speed effects, and ideally you’ll want to shoot with a shutter speed of around 30 seconds.
To access these long exposures you’ll need the assistance of a Neutral Density (ND) filter. These are darkened plates of glass or resin that sit in front of your lens and restrict the amount of light passing through to the sensor; a bit like wearing a pair of sunglasses. They’re available in different strengths – also called ‘stops’ – and come as either circular screw-in filters, or square filters which also require a filter holder to slot in place.
Use a Neutral Density filter to restrict the light reaching the sensor
The most effective Neutral Density filters reduce the light by 10-stops, and are known as ‘big stoppers’. Every ‘stop’ increase or decrease represents a doubling or halving of the amount of light, so a 10-stop filter reduces the light passing through to the sensor by a factor of 1000! This means a 1/30sec shutter speed becomes a super slow 30 second exposure when a 10-stop ND filter is fitted to the lens.
Of course the speed you want to shoot with will depend on the degree of blur you’d like to create in your images, and the speed of any moving subjects. Most cameras are limited to a minimum shutter speed of 30 seconds, but if you want to capture an even longer exposure you’ll need to shoot in Bulb mode and use a shutter release cable. When venturing into Bulb mode you’ll need to consider your f-stop and perform some calculations to work out your exposure, or if maths isn’t your strong point you can’t go far wrong with trial and error! For most subjects though, a 30 second exposure is perfectly long enough to capture a pleasing blur. Follow these 5 easy steps to shoot your own artistic long exposures.
Step 1
You’ll definitely need to use a tripod when using a long exposure, as any slight movement during the shot will result in camera shake and blur the entire image. To stay super steady, try and avoid using the thinner tripod legs if you can help it, don’t extend the centre column and if possible weigh the entire setup down by hanging your camera bag from the tripod collar.
Using a tripod is essential when shooting long exposures
Step 2
Switch your camera to Manual mode (M on the mode dial) and dial in a shutter speed of 1/30sec, set your ISO to 100 and then adjust your aperture until your camera’s light meter is giving a balanced exposure.
Set your camera to shoot in Manual mode
Step 3
Frame up and focus on your subject and then set your focusing mode to manual by flicking the switch on your lens or camera body to keep it locked. It’s not possible to focus when the ND filter is attached as there’s not enough light passing through for the AF sensors to work, and also make sure your composition is correct as you can’t see through the lens either.
After setting the focus, switch to manual AF so the focus stays locked
Step 4
Before you shoot you should make sure your viewfinder is covered. Some cameras feature a curtain in the eyepiece which you can close down, but if not you can cover it with a piece of dark tape or drape a cleaning cloth over it. This is because light can sometimes leak into your camera during longer exposures, and you’ll discover strange coloured blotches on your image which will ruin your shot.
Make sure the viewfinder is covered to avoid light leaks
Step 5
Fix your 10-stop Neutral Density filter to the front of your lens, and then adjust your shutter speed from 1/30sec to 30 seconds, to take into account the reduction of light from the filter. Set a 2sec self timer or use a shutter release cable to take the shot to avoid jolting the camera when you press the shutter button. Patiently wait half a minute, and then admire your skills on the camera screen!
Attach your Neutral Density filter in place to extend your shutter speed
. digitalrev.com2017-9-29 03:00
