Shutter Speed

The following are a few notes from a lecture given on September 13th, 2012.

The shutter has two main functions
1. It controls time (the length of time/exposure to light the image sensor receives)
2. It controls motion (ie: sharp or blurred)

Additionally, the shutter (like the aperture) controls the amount of light that gets through to the sensor.

Shutter speed is measured in seconds
Or in most cases fractions of seconds. The bigger the denominator the faster the speed (ie 1/1000 is much faster than 1/30) In most cases you’ll probably be using shutter speeds of 1/60th of a second or faster. This is because anything slower than this is very difficult to use without getting camera shake. Camera shake is when your camera is moving while the shutter is open and results in blur in your photos. If you’re using a slow shutter speed (anything slower than 1/60) you will need to either use a tripod or some some type of image stabilization (more and more cameras and lenses are coming with this built in).
Shutter speeds available to you on your camera will usually double (approximately) with each setting.
As a result you’ll usually have the options for the following shutter speeds – 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8 etc. This is good to keep in mind since aperture or f/stops also double the amount of light that is let in. This is important to keep in mind because knowing how shutter speeds and apertures relate will give you the ability to adjust both for desired effects in your photography. Something that regular camera-hobbyists don't necessarily know.

When considering what shutter speed to use in an image you should always ask yourself whether anything in your scene is moving.
...and how you’d like to capture that movement. You can freeze the moment or let the moving object intentionally blur (this gives your photographs a sense of movement).

To freeze movement in an image:

You’ll want to choose a faster shutter speed
and to let the movement blur
You’ll want to choose a slower shutter speed.
The actual speeds you should choose will vary depending upon the speed of the subject in your shot and how much you want it to be blurred.

Remember that thinking about Shutter Speed in isolation from Aperture and ISO is not really a good idea. As you change shutter speed you’ll need to change one or both of the other elements to compensate for it.

image found here.