Definition of Shutter Speed

This is the length of time the shutter stays open for. This effects the amount of light that reaches the image.

Using Shutter Speed to control light

It is quite obvious the affect shutter speed will have on an image. The longer you leave your shutter open the more light will reach your photo and the brighter it will become. To short of a shutter speed your image will be dark. To long of a shutter speed and it will become to light. Shutter speed can also affects how clear or blurry all or part of the image is, but we will talk about that later (under Create Effects Of Shutter Speed).

Measuring Shutter Speed

Shutter speed is always measured in seconds. In photography one second is a long time, however long exposure photography can be several seconds or even minutes.

You may see shutter speeds on your camera like the following:

Trading Shutter Speed for Aperture

Shutter Speed along with other factors control the amount of light that comes in the camera. One factor is the aperture setting. The reason why we will talk about aperture is because it is easy to calculate the trade off between shutter speed and aperture. Each f-stop is a half (or double) the amount of light.

Lets you are shooting at 1/30th of a second shutter speed and your aperture is f/4.0 however but you are getting camera shake in your image because the shutter speed is to slow. You then decide to increase your shutter speed to 1/60th of a second. Now you have to “stop-up” your aperture that means you have to increase your aperture. To gain back the light you need to double it by going to f/2.8. The reverse is also true if you are shooting.

(To better understand f-stops (f-numbers) and how it works with your aperture please read the page on aperture)

Camera Shake and  Shutter Speed

There are a few things to consider when your choosing a shutter speed. When shooting with out a tripod you are likely to get camera shake which will make your picture look blurry. To avoid this you need to increase your shutter speed. The rule of thumb is to use the inverse of your focal length. This means if you are shooting at 50mm you shutter speed should be at least 1/50th of a second, if you are shooting at 100mm you should have a shutter speed of at least 1/100th of a second and so on. This will keep your image crisp.

Creative Effects of Shutter Speed

There are a couple ways to freeze a moving subject. One way is to use your flash, however, when there is a lot of light the flash is not very effective. A fast shutter speed is the another option. With a fast shutter speed you can freeze your subject in place making it a sharp image.

For example, the photo on the right was taken at 1/500th of a second. This froze the little water fountain in place allowing the water droplets to be seen.  You will need to adjust the shutter speed according to the speed the subject is moving. By using a higher ISO and larger aperture you can use a faster shutter speed, however, higher ISO and larger aperture will also have other effects on the image.

To get a little more creative, lets talk about longer shutter speeds. Have you seen those photos with a water fall that is all smooth and soft? That is caused by a long shutter speed. The longer you leave the shutter open the smoother the water will look. This means, however, that you will have to reduce the light by other means such as a smaller aperture, lower ISO, or filters.

The water fall photo on the right was taken at 1 second. Normally a photo like this would be all white because of too much light. To reduce the light a f-stop of f/32 was used and a low ISO of 100.

You can also use long shutter speeds for night photography. With night photography you do not have to worry as much about too much light. the city photograph on the right was taken around 4 seconds.

When you see a crisp, sharp image of a car but the background is blurry (making the car look like it is moving fast) is accomplished with a long shutter and a technique called panning. While using a long shutter speed you have to move the camera keeping the subject in the exact same location of the image. This is tricky and takes lots of practice.

So from a creative stand point we see that afast shutter speeds cause the image to be sharp and crisp. Long shutter speeds can cause parts or even all the the image to be burred.

Conclusion

Shutter speed is used to controls the how much light goes to your image. It is also used to prevent camera shake by using fast shutter speeds or can be used for creative effects by using  short or long shutter speeds.