Understanding “Shutter Speed”

Last modified on 2010-06-18 14:53:16 GMT. 3 comments. Top.

Shutter speed also affects the exposure of your picture. A shutter is a window or door in front of the film plane or image sensor that opens either vertically or horizontally to let in light and then closes to block out light. The longer that door is open the more light comes in. Shutter speed times are a little easier to understand. For normal everyday photography a shutter will stay open for about 1/250 th of a second. If the shutter stays open for 1/100 th of a second then more than twice as much light comes in. If the shutter stays open for 1/500 of a second only half as much light come in. Shutter speeds can be as fast as 1/8000 of a second.

Shutter speeds are also referred to in the scale of “stops.” Stops in the shutter speed category is easy to remember. Every time you double the speed you have step down by one stop. I.e. from /1100 to 1/200 is a one stop down in the amount of exposure, 1/200 to1/ 400 would be one more stop down, etc.

The faster the shutter speed the more accurately you can freeze the action of a moment but it lets in only half as much light with each “stop down”.

Here is an example of two pictures taken at different shutter speeds:

Shutter Speed of 1/6000 sec

Shutter Speed of 1/50 sec

Panning was employed to blur the cluttered background. This shot also has a much different feel than the one above. The movement of the rider and horse is emphasized in this shot

There are creative times that you may want to take an action picture with a slower shutter speed to emphasize the action allowing the picture to blur as in the bottom picture above. There are also times you may want to stop the action and freeze the subject so that it is crystal clear as in the shot below. Perhaps a slice of history frozen in time would be the theme of the shot below.

That is the creative side of using various shutter speeds. In order to empoly these techniques you much set your camera on either “shutter pritority mode” or “manual mode.” Using “shutter priority mode” will allow the camera to automatically set the aperture value. If you use “manual mode” you will have to set the aperture value yourself. There are times that manual mode is very valuable but that will be a discussion for a future article.

The limitations and technical side of shutter speed

Now, if slower shutter speeds let in more light it would seem logical that you might let in too much light if you continue to lengthen the shutter speed? Yes that would be true however when you lengthen your shutter speed you should always reduce the size of the aperture to keep the proper amount of light in balance. It might be compared to filling a gallon bucket with water from a faucet. There are two ways to do it (with many variations in between). You can turn the water on very slowly and let out just a trickle of water but it will take longer to fill the gallon bucket. Or you can turn the water on full blast. This will take a shorter time to fill the bucket but it will still be the same about of water when the bucket is full. Two different speeds, two different amounts of flow, but still the same amount of water. The aperture is compared to how wide open you turn the faucet on. The shutter speed is compared to the amount of time it takes to fill the bucket. The bucket is the measure of the amount of light it takes to expose the picture correctly.

For those of us who began in photography when there was no truely automatic cameras, we had to remember to set all of this manually every time we took a picture. We had to use external meters to measure how much light was needed for each situation and then set each of these settings manually. Or we tried to make a lucky quest (which was more often wrong than right).

Today’s world of automatic cameras allows us to avoid thinking about much of this mechanical stuff when we shoot a picture. The reason many more people take pictures today than they did in the 50’s, 60’s, 70’s and even the 80’s is because they don’t have to bother with setting anything on the camera.

But the more you know about APERATURE and SHUTTER SPEED and ISO settings the more creative you can become with your camera. The knowledge and use of these three things is what separates the world of the snap shot shooter from the creative photographer. This is true whether you shoot with film or a digital camera.

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