Freeze action or show the passage of time
If you want to capture still photos of fast motion (like pressing pause on your VCR or DVD) you have to use a fast shutter speed. Many sports use very fast shutter speeds to capture the peak moment and freeze it in time.
If the subject of your photo is not moving, or you want to show the passage of time (with a running river or waterfall), then you can use a slower shutter speed.
The Numbers of Shutter Speed
There are two different types of shutters in cameras. Some cameras have a plate that covers the image sensor of the digital camera. When you push the button to take a photograph, the plate flips up and lets light onto the camera's image sensor.
Another type of shutter is called an iris, because it works somewhat like your eye. When you push the button to take a photograph, the iris expands and lets light onto the camera's sensor.
Either way, the shutter speed is the amount of time that the plate stays up or the iris stays open. Shutter speed is measured in fractions of seconds and seconds.
Here is an example of shutter speed numbers, from fast to slow:
1/2000 1/1500 1/1000 1/750 1/500 1/350 1/250 1/180 1/125 1/90 1/60 1/45 1/30
Realize that 1/2000 of a second is incredibly fast and is not a shutter speed that you will typically use. The most common shutter speeds are anywhere from 1/500 to 1/60. If you want sharp photographs while holding the camera in your hands, you cannot use shutter speeds much slower than 1/60 because it's hard to hold the camera steady. Slow shutter speeds blur motion, and you are creating motion by holding the camera in your hands. You can solve this camera shake problem by stabilizing the camera on a tripod.
Some of the new digital camera models offer an anti-shake feature. These features produce crisp photos even when you are hand-holding the camera with a shutter speed less than 1/60.
Digital Camera Shutter Speed Display
The most common shutter speeds are measured in fractions of seconds. However, camera displays do not have enough room to show you numbers like 1/800.
Instead, digital cameras just display the bottom number: 800. If you look at your camera's display and it tells you that your shutter speed is 125, this does not mean 125 seconds. That would make for some very long and boring picture taking.
Instead, most cameras indicated seconds with a double quote after the number. So a one second shutter speed is displayed as 1". A 30 second shutter speed is displayed as 30".
Shutter Speed and The Real World
|A hummingbird is hovering above a flower, and you don't want it's wings to be blurry||Very fast shutter speed||2000 to 4000|
|Your kids are playing soccer, and you want the images to be sharp and clear||Fast shutter speed||500 to 1000|
|You are taking a portrait of your favorite pet, and your pet is being polite and sitting still||Moderate shutter speed||125 to 500|
|A carousel is spinning and you want to show how fast it is going by letting the horses blur||Slow shutter speed and tripod||8 to 60|
|You want to take a photograph of your favorite building at night||Very slow shutter speed and tripod||8" to 30"|