How shutter speeds affect exposure and the way motion is recorded.
Just like the aperture, shutter speeds also have their creative benefits, allowing you to control how motion is recorded in your shot.
First though, let’s see how shutter speeds can affect exposure…
How shutter speeds can affect exposure
While the aperture determines the strength of the light reaching your camera’s sensor, and controlled by a variable diaphragm that can be open at different apertures to let more or less light through the lens, the shutter speed controls the duration that the sensor is exposed to the light entering through the aperture.
Long shutter speeds let me more light in, while short ones result in less light hitting the chip. By balancing out the aperture and the shutter speed for the lighting conditions in front of you, you can set the correct exposure for the scene.
For instance, if you wanted to shoot a shallow depth-of-field image on a bright day, you’d set the aperture wide-open at f/2.8, which would let as much light through as possible. With this level of light hitting the sensor, you’d need a fast shutter speed to avoid over-exposing the image.
However, if you wanted to shoot a landscape under the same lighting conditions, you’d set your camera at f/16 to ensure detail was obtained throughout the scene.
This reduction means there’s less light hitting the sensor due to the smaller aperture diaphragm, meaning you’d need a longer shutter speed than you did when shooting at f/2.8 to ensure the scene was exposed correctly.
If the prevailing light drops even further – it may become overcast, then you’ll need a longer shutter speed still, to make sure your shot isn’t under exposed (not enough light hitting the chip).
Just like the aperture, the shutter speed is measured in ‘stops’, with each stop doubling or halving the exposure.
As an example, changing the shutter speed by a stop from 1/500sec to 1/250sec doubles the exposure time.
Most modern DSLRs will also allow you to control the shutter speed in either 1/3 or ½ stops should you wish as well for more precise exposure control. A camera’s shutter speed range will vary from model to model, but in the main, 30secs-1/4000sec is the norm, with some top-flight models shooting at up to 1/8000sec, while a compact camera shutter range is not quite as broad.
For longer exposures than 30secs, cameras are equipped with a Bulb function – normally the next click after 30secs, with the duration dependent on how long you keep the shutter button depressed for.
Shutter speed and movement
The shutter speed is not only fundamental in controlling exposure, but it also has it’s own creative options as well. By adjusting the shutter speed, you can vary how any movement in your shot is recorded.
Fast shutter speeds are essential is you want to freeze any action in a shot. The incredibly short period the shutter will be open for during the exposure means that your subject will be rendered perfectly still and frozen in time.
While fast shutter speeds are great for a range of sporting subjects – swimming, football and rugby spring to mind, fast shutter speeds can have a negative effect when used on other subjects – specifically cars or bikes.
While there are exceptions, fast shutter speeds can leave fast moving cars looking like they’ve stopped on the track – with the wheels frozen and a static background, the energy can drain out of the shot.
However, by dropping the shutter speed much lower – around 1/125thsec or even 1/60sec (though again, this will depend on how fast your subject is traveling), and tracking your subject smoothly as it passes from left to right, it’s possible to keep your main subject in focus (the moving car or bike) as you’re moving in time with it, but due to the slow shutter speed, reduces the background and wheels to a blur.
This technique is known as panning, and is a fantastic way to maintain energy and speed in your shot.
Apart from shooting action, they’ll be other times when you want to convey movement in your shots. But rather than moving with your subject as you do when you pan, keep the camera still and extend the shutter speed so the shutter is open long enough to record any movement (again, this will vary depending on how fast your subject is moving).
The background will remain unaffected by the extended shutter speed because the camera hasn’t moved, but the element of the shot that’s moving will become a blur – this works really well with waterfalls for instance, as they become ultra smooth with rounded edges.
Shutter speed and shake
A lot of the time, blurry images aren’t the result of the camera’s autofocus not working correctly, but the effect of camera shake when handholding your camera.
It’s a common problem that can be attributed to using a shutter speed that’s slow enough to record any subtle movements when you take a shot. This results in a slight smear to your image. Understanding how slow you can shoot handheld and still achieve pin-sharp shots will work wonders for your photography.
While a shutter speed of 1/15sec or 1/8sec may appear to be more than fast enough to take a sharp shot handheld, it’s actually still slow enough to register any camera shake in your shots.
Good technique and the way you hold the camera, with your left hand supporting the underneath of the lens, can reduce camera shake to a point. However, in most cases, you’ll need a faster shutter speed to avoid any risk of camera shake. If your lighting conditions won’t allow a faster shutter speed, then a tripod is called for, offering a firm base for your kit.
The slowest shutter speed you can shoot with handheld and still achieve sharp shots isn’t fixed and will vary depending on the focal length of the lens used.
You may be able to shoot as low as 1/15sec with your 18-55mm kit lens, but you’ll be hard pushed to get a sharp shot at the same shutter speed if you use a 55-200mm telephoto zoom. This is because any camera movement when you handhold your camera is exaggerated due to the extended, zoomed-in focal length of the lens, which requires you to shorten the exposure with a quicker shutter speed.
All you have to do is roughly match the shutter speed to the focal length of the lens you’re shooting with, but you do have to take into account the focal length magnification of your camera.
For example, if you’re shooting with an 18-55mm lens at 18mm, you’ll need to multiple that by 1.5x for a Nikon DSLR. This will produce a 35mm focal length equivalent of 27mm, so you don’t want to use a shutter speed slower than 1/30sec.
Shooting at 200mm, it has a 35mm focal length equivalent of 300mm, so will require a shutter speed no slower than 1/500sec – one stop slower and you’ll be shooting at 1/250sec and less than the focal length of the lens.
This is just a rough guide – you may have a very steady hand matched by sound technique that allows you to shoot even slower, while some may find that they need to shoot a little faster.
In an effort to combat the risk of camera shake and allow photographers to shoot at shoot at lower shutter speeds than would normally be possible and still pull off sharp shots, manufacturers have developed anti-shake systems.
These are either lens based, such as Canon’s Image Stabilizer (IS) or Nikon’s Vibration Reduction (VR) technology, which uses a lens-shift system to detect and correct camera shake. Other systems such as Sony’s SteadyShot INSIDE feature a sensor-shift mechanism to do a similar job.
Both systems aim to offer between a 3-4 stop reduction in the shutter speed required to achieve a sharp, handheld shot. This means that rather than having to shoot at 1/500sec with your 200mm lens, you can drop the shutter speed by 4 stops and shoot as slow as 1/30sec, but still manage to achieve a sharp shot.
Handheld shutter speed recommendations
|Focal length||35mm focal length equivalent (1.5x)||Shutter speed required||Shutter speed (with 4 stop anti-shake)|
Shutter speeds: Try it yourself
We’ve talked about the principals of shutter speed, so let’s put it to use. Grab you’re kit out of your camera bag and we’ll show you how to set-up your camera so you can freeze the action or blur motion. Follow our step-by-steps to find out how…
Step 1: Shutter Priority
Because we want to control the shutter speed of the camera, set the camera in to Shutter Priority mode – this will allow us to control the shutter speed, while the camera will set the aperture for a correctly exposed shot.
This will either S or Tv on your camera’s mode dial depending on manufacturer.
Step 2: Set aperture
Now dial in your shutter speed and to freeze the water, we need a fast shutter speed of 1/500sec.
You may find if the light is fairly weak that the camera may not be able to set an aperture wide enough to correctly expose for the scene, so increase your ISO until this is possible.
Step 3: Review image
Frame-up your shot and at this kind of shutter speed, handholding shouldn’t be a problem.
Fire the shutter and then review your shot – if you can still see some blur in the water, you’ll need to increase the shutter speed further.
Try setting it at 1/1000sec and then try again.
Blur the motion
Step 1: Decrease the shutter speed
With the camera still set in shutter priority, reduce the shutter speed to 1/15sec – this should be enough to capture any movement from the water.
With a longer exposure than previously, the camera will set a much smaller aperture, to restrict the light getting to the chip and balance the exposure.
Step 2: Change ISO
In good light, even with the lens stopped right down to f/22, you may find that you need to reduce the ISO to a lower sensitivity – 100 or 200.
At a slow shutter speed such as 1/15sec, it’ll be tricky to handhold and still achieve a sharp shot, so a tripod maybe called for.
Step 3: Focus
With your image framed-up again, set the camera to self-timer if you’re shooting on a tripod – even pressing the shutter at this shutter speed can result on camera shake.
The self-timer eradicates this. Fire the shot, and if there’s not enough blur, extend the exposure.
Author: Matt Tuffin