Let’s talk about shutter speed! What is it? What does it do to your pictures? How do you control it to get the images that you want? For many of you, this is something you already know very well, but for others this will be helpful information.

The quick and simple definition of shutter speed is this: the amount of time that the camera’s shutter curtain is open, allowing light to reach the camera’s sensor or film. A fast shutter speed allows very little light to expose the sensor or film, while a slow shutter speed allows a lot of light to expose the sensor or film. Shutter speed is one of three elements of the exposure triangle, with aperture and ISO being the other two.

Some examples of common shutter speeds are 1/15, 1/30, 1/60, 1/125, 1/250 and 1/500. There are, of course, many other shutter speeds, this is far from a comprehensive list. 1/15 is an example of a slow shutter speed, and 1/500 is an example of a quick shutter speed. You’ll note that these are fractions, as in fractions of a second. You’ll also note that they’re half or twice as long as the shutter speed on either side, which means that 1/60 lets in half as much light as 1/30, and 1/15 lets in twice as much light as as 1/30.

If the shutter speed is too slow, you’ll have blur from camera shake, unless you’re using a tripod. A rule of thumb for the slowest hand-held shutter speed (without the help of image stabilization) is this: whatever the focal-length of the lens is (or in the case of Fujifilm X, the 35mm-equivalent focal-length), the shutter speed should be a similar number. For example, if the lens is 12mm, which has a 35mm-equivalent focal-length of about 18mm, the slowest hand-held shutter speed is around 1/15 or 1/20. If the lens is 90mm, which has a 35mm-equivalent focal-length of 135mm, the slowest hand-held shutter speed is around 1/125. With good techniques, you can often get a sharp picture with even slower shutter speeds, but that takes practice. Otherwise, you’ll have to use a tripod.

Shutter speed is about motion, either freezing it or showing it. A slow shutter speed will show motion (such as the picture at the top of this article, where the water is blurred), while a fast shutter speed will freeze it (such as the picture directly below this paragraph, where the moving car is sharp). In the first picture below, which was captured with a 1/450 shutter speed, you’d never know that the car was zooming by, because the motion was frozen. The second picture below, which was captured with a 1/80 shutter speed, shows the motion through the car’s blur. The third picture below, which was captured with a 1/60 shutter speed, shows the motion through panning, where the car is sharp but the background blurred from the sweeping lens.

You can show motion in a photograph using a slow shutter speed, and some of that motion might not be immediately obvious. In the first picture below, the firework is moving during the exposure, showing colorful light streaks. In the second picture, the earth’s rotation makes the stars streak. In the third picture, intentionally shaking the lens creates an abstract picture through the camera’s movement.

A fast shutter speed will freeze motion. If there’s some fast-moving object that you want to capture still without blur, you need a quick shutter. This might be a car driving down the road, running kids or jumping pets. Just how fast the shutter needs to be depends on how fast the object is moving, how close it is to the lens, and the focal-length of the lens. The picture below is an example of freezing a moving object with a fast shutter speed.

It takes much practice to master the shutter, but with practice you’ll know exactly what shutter speed you need to get the picture that you want. There are many variables, so there’s no one-size-fits-all recommendation. Don’t be afraid to experiment. You might fail, but you’ll learn, which will lead to success. Be creative! Put the camera on a tripod and try some different slow shutter speeds. Try photographing your kids or pets using a fast shutter. Pretty soon you’ll be a master of the shutter, totally in control of your camera.