Photography Lesson: Shutter Speed

[Diane Margetts]

The shutter speed refers to the amount of time that the shutter of the camera is open and the film/sensor is exposed to the light.

Shutter speeds on modern digital cameras are generally expressed as 1/x-th of a second. The range of shutter speeds can be expressed as: 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, etc. with each one being a fraction of a second. Each fraction of a second in this series is half the amount of time as the one to the left.

The speeds available on a camera depend on the design of the shutter and type of camera, itself. Normal settings will include speeds of 1 to around 8000. A shutter speed set to 1 indicates that the shutter remains open for 1 second. A setting of 2 will indicate that the shutter will open for 1/2 second. If the shutter speed is set to 60, the shutter will remain open for 1/60 of a second, etc. Every setting on the shutter speed is also referred to as a "STOP". Each STOP will expose the film for exactly double or half the time, depending on the direction in which the setting was made. The faster the shutter captures that image, the more likely the image being shot will be clear and sharp, while conversely a slow shutter speed will cause fast moving objects to blur. Keep in mind, that faster speed allows less light to enter the camera which can result in underexposure.

It is very important to choose the right shutter speed to make sure you avoid blurring of the moving objects or camera shake. Avoid camera shake by setting teh shutter to a faster speed than the one used when you captured some blur in your photo, which is largely dependent on the 35mm focal length equivalent that was used. In other words, shooting with a 50mm lens, your shutter speed should be 1/50 or faster to prevent visible blurring. The same applies to zoom the lenses. For example shooting at 300mm, set the speed to at least 1/300 of a second.

Note that some cameras and lenses have built in image stabilizers to help prevent camera shake. When using this feature or having the camera on a tripod, you can set the shutter speed much lower than what is mentioned above.

Crop Factor

Another important thing to remember with digital cameras is a crop factor. The rule mentioned above applies to the equivalent of a 35 mm film camera. The sensors in DSLR cameras are physically smaller than 35mm, making the image projected onto them appear larger than they would on a 35mm film strip. In other words, sensors smaller than one frame of 35mm film have a multiplying effect on the focal length of a lens. On a camera with a 1.6 field of view multiplier, a 100mm lens would be equivalent to 160mm lens because of the crop factor.

How To Set Minimum Shutter Speed for Hand-held Shots

To set the correct minimum speed for hand-held shots, use the following method (where 1.6 is a crop factor multiplier; this differs for every camera and no crop factor applies to film cameras.)

- for a 50mm lens the speed should be at least 50 x 1.6 = 1/80s
- for a 300mm lens it is 300 x 1.6 = 1/480s

Bottom line is, if you're using 28mm lens on your DSLR, you are effectively using 45mm lens (when your field of view multiplier is 1.6). Some newer DSLR models use 1:1 equivalent to 35mm film. Check your camera documentation to find out what your sensor's size is.

Since 35mm film is the standard by which everything else is determind, then it logically follows that no crop factor calculations are needed for film cameras.

Slow Shutter Speed With Daylight Exposure

If you have a more advanced camera and would like to play with manual settings, then choosing a shutter speed is clearly important. You need to remember that shutter speeds are very closely connected to movement. If you need to freeze an action, use a fast shutter speed.

Shutter Speed Techniques

Panning. This is also known as "Following the subject as it moves". Select a slow shutter speed and follow the subject as it moves, pressing the shutter button as you pan. If you did it right, your subject will appear sharp, making it appear as if it hasn't moved position., but the background will be blurred making the subject look like its hurtling along. You can try this on moving subjects such as joggers, cars, airplanes and others.

Another technique for creating a sense of movement is to keep the camera at a fixed point, choose a slow shutter speed, then press the shutter button. By using this technique, the background will be sharp and the subject will be blurred as it passes across the viewfinder. The subject can often look too blurred resulting in a shot that has no impact at all. That is why it requires a lot of skill to get the detail right. It enhances the feeling of speed or action in the scene.

The third technique is similar to the example mentioned above, but it's used to eliminate the subject. It is employed by architectural photographers who want to photograph a building without people getting in the way. If the shutter speed is slow, people will still appear as blurred and distracting objects, but if it's long enough the blurred person walking across the scene will be so blurred it won't even be identifiable and will not affect the picture.

By choosing slower shutter speed (4 seconds, f3.2), walking people in the background have been eliminated. You can see couple of "ghosts" in there. Mother with the stroller was standing still while this shot was taken.

Remember that if your shutter speed is slower than 1/30, this could make it difficult for you to hold the camera completely still while the shutter is open. Moving the camera slightly while the shutter is open is known as "camera shake" that makes the entire image a bit blurry. A common rule is not to hold the camera in your hands if you plan to use shutter speeds slower than 1/30. Instead, rest it on something or use a tripod.

Fast Shutter Speed In Daylight

Fast shutter speeds can be used to produce the effect that movement has been frozen. The subject must be moving, and the camera still.

Imagine a car or a person passing quickly across a chosen viewpoint. If the shutter speed is set at 1/60s or less the moving subject would appear blurred. However if the shutter speed were 1/250s or more the moving object would be clear, "frozen" in action.

Use this subject freezing shutter speed if you want to stop a goal-scoring football player in their tracks, freeze a jogger or capture a flying bird in mid-air. It is not very effective for cars though as it only looks like you took a picture of a parked car somewhere.

Use flash to freeze movement

Another way to freeze movement is by using the flash. The light from the flash is emitted in a fraction of a second and the position of the subject at that moment will be isolated in the image. This technique is also called Slow Sync Flash and is described in detail in lesson 12.

Different Shutter Speeds And Their Use

30 seconds and above - Perfect for night shots. With this setting, you get the result of milky smooth water from a waterfall at dusk or dawn. Leave the shutter open for at least a couple of hours, directed at the night sky, and you should end up seeing star trails on your image as the Earth rotates.

1 second - Use this speed if you want a spooky nice effect at a wedding reception. Set your camera's shutter speed to 1 sec and aperture to approximately f.8. Snap a picture while moving the camera about. The flash effect will "freeze" your subject, but the long shutter speed will give some astonishing background effects.

15th/30th/sec - This is good for dusky or dawn landscapes. These speeds are also good for panning shots of moving objects likes planes, joggers, etc. Panning creates a feeling of motion in the background while the subject stays in focus.

60th-250th/sec - Anything in this range is good for everyday general photography. In normal light, these speeds should give adequate depth of field from the aperture setting for most subjects, whilst allowing you to hand hold your camera without causing camera shake.

1000th-8000th/sec - These speeds will freeze most objects in their tracks. To be able to shoot at these speeds, you will need bright sunshine, a fast lens (f2.8/1.4), or a high ISO (400/800/1600).

Thanks to low shutter speeds, images like this can be taken at night. A tripod is a must in night photography.

Shutter Priority

Most of the better compact cameras and SLRs have the Shutter Priority system. When the shutter speed is adjusted manually, the camera selects the correct aperture automatically given the light conditions.

It takes time to understand the basics of shutter speed but you'll be surprised how much your photography skills will improve when you master these few basic techniques.

[F, Calla & Luca]

These lessons are great. Thanks.

[Nancy, Ned, Clancy, and Charlie]

Thanks again!