Shutter speed, aperture, & ISO make up the EXPOSURE TRIANGLE of photography. All
three work in tandem, and to master them is half the battle of becoming a good
photographer.
Today I will talk about shutter speed.
Think of Shutter Speed as a door: The longer it stays
open, the more light it lets in. A
cameras shutter normally remains closed. When the shutter button is pressed the
camera’s shutter opens for a given period of time.
Shutter speed is measured in seconds – or in most
cases fractions of seconds. Here are some common shutter speeds.
1/1000 1/500 1/250 1/125 1/60 1/30 1/15 1/8 3/4 1/2 1
sec "B"
The bigger the denominator, the faster the shutter speed. A change in shutter speed from one stop to
the next doubles or halves the amount of light that gets in. If you increase either the shutter speed or
aperture, and decrease the other you let the same amount of light in. A shutter speed of 1/100 sec is open for
twice as long as 1/200 second.
The human eye “sees” at 1/60 of a second. In most cases you will probably be using
shutter speeds of 1/60th of a second or faster. Anything slower than 1/60 is
very difficult to use without getting a blur in your photos (camera shake). If you
are using a slow shutter speed (anything slower than 1/60) you will need to
either use a tripod or some type of image stabilization. Many cameras have a form of stabilization
built in. Some cameras also give you the
option to shoot in ‘B’ (or ‘Bulb’) mode. Bulb mode lets you keep the shutter open for
as long as you hold the shutter button down.
When considering what shutter speed to use you should
always ask yourself whether anything in your scene is moving and how and if you
would like to capture that movement. If there is movement in your scene you
have the choice of either freezing the movement or letting the moving object
intentionally blur.
Motion is not always bad. There are times when motion
is good. When you’re capturing a photo of a waterfall and want to show how fast
the water is flowing, or when you’re capturing a shot of a racing car and want
to give it a feeling of speed, or when you’re capturing a shot of a star scape
and want to show how the stars move over a longer period of time. In all of
these instances choosing a longer shutter speed will be the way to go. However,
in all of these cases you need to use a tripod or you’ll run the risk of
ruining the shots by adding camera movement (a different type of blur than
motion blur).
To freeze movement in an image you’ll want to choose a
faster shutter speed.
Photography
is a compromise. You are balancing time (shutter speed) versus
quantity of light (aperture/opening of your lens). Along with the aperture
setting, the shutter is controlling the light reaching the camera’s sensor.
Most likely, your camera
has several different “modes” that allow you to select the priority you want
the camera to capture the image. Once
that priority is chosen, several other factors are automatically selected.
One such mode is Shutter Priority. You set the shutter speed and the camera will
attempt to deliver a good exposure. This may be indicated by a "S"
icon or "Tv". Use Shutter
Priority mode when you’re shooting subjects in motion. Use a fast shutter speed
to freeze motion. Use a slow shutter
speed to render an object in motion with an artistic blur. The shutter speed
needed to freeze action depends on how fast the subject is traveling and how
far you are from the subject… we will discuss this later … The shutter speed
controls how movement is recorded.
Often times Shutter
Priority is used when action is expected; sport activities, wildlife, weather /
wind movement, auto or foot races. A
fast shutter speed will freeze action.
The image on the left was captured with a shutter speed of 1/80. The image on the right used a shutter speed
of 1/15.
Another mode that utilizes the
shutter speed as a priority is the “B Mode” or “Bulb” setting. Set your camera to B mode when you want to
capture pictures of night scenes, fireworks, and any other scene that requires
a lot of light to properly exposure the image. When you shoot in this mode, the
shutter stays open as long as you have the shutter button pressed. This is a
time exposure. When you shoot a time exposure, place the camera on a tripod to
ensure a blur-free shot. You will also need a cable release or a remote
trigger, which lets you open the shutter without pressing the shutter button. Bulb
Mode is often used for capturing images of the night sky and stars.
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