How Does Shutter Speed Work?

Have you ever wondered why your pictures are blurry? You have only recently acquired a professional camera and have no idea how to use it? The key to improve your images could be the shutter speed, a detail often overlooked by beginners.

Let's start simple. Shutter speed, defined in simple terms, is the amount of time that your shutter remains open as you capture an image. In film photography, this indicates the amount of time your film was exposed to the scene, while in digital photography it refers to the image sensor.

If you want to get a more detailed explanation, you should learn first what a shutter actually is. This mechanical device is located in front of the sensor in digital cameras. It controls the time during which the sensor is exposed to the light.

It is formed by two pieces, one that opens to start the exposure to the light, and one that moves to shut it down.

In your camera, you will see the shutter speed measured in fractions of second (or simply seconds). The bigger the denominator, the faster the speed.

Extra slow speeds will be marked on full seconds. These speeds are useful when you are in a low light setting or when you are trying to trace movement in a shot.

Bulb mode allows you to keep the shutter open for as long as you keep your finger on the button. It is useful for making special effects like light painting but it would probably not be adequate if you are trying to “freeze” the action.

With a long exposure shot, you want to obtain a clear image. For this kind of shots you will usually use speeds or 1/60 or slower. This can be tricky since your shutter will be open for a long time and if you don´t use a tripod, the movement of your hand will result on a blurred effect.

With a long exposure shot, you want to obtain a clear image. For this kind of shots you will usually use speeds or 1/60 or slower. This can be tricky since your shutter will be open for a long time and if you don´t use a tripod, the movement of your hand will result on a blurred effect.

On the contrary, a faster shutter speed will allow you to freeze the action, something useful in sports photography, for example. This is not a rule set in stone, because you could use the blurriness to create the illusion of movement. You can see this result on “silk” effect used when capturing images of cascades.

There is a final detail you need to consider before fooling around with your shutter speed. The focal length of your lens could impact significantly your speed values. To make sure you are taking this factor into account, use the “thumb” rule.

This rule means you choose a shutter speed with a denominator larger than the focal length you are using. It sounds complicated, but let's take a closer look. Imagine you have a lens that is 50 mm. You would use speeds higher than 50, meaning 1/60 is safe to go.

But if you change to a 200 mm lens, your basic shutter speed could go up to 1/250.