A noun as defined in the dictionary as being the time for which the shutter is open at a given setting.
Quickly put, shutter speed is what you use to determine the sharpness of your image relative to the subject.
This is achieved by setting your shutter speed via the dials on the top of your camera, or via the shutter dial on most DSLRs.
For example, you may want to capture a fast moving object like a ball flying through the air. If you use a shutter speed that is slow, that ball will be blurry, but show movement. But if you use a fast shutter speed, the ball will look like it’s been frozen in time.
Of course, artistically, it’s up to you how you want to shoot the ball – I am just providing an example.
Movement in your scene is what shutter speed is all about. That’s how I look at it, anyway.
There’s a lot of technicalities that go into shutter speed – for example, not using a shutter speed which is shorter than the focal length of your lens – but that’s for another post.
You can set your camera to Shutter Priority mode, meaning you choose the shutter speed you want and the camera will determine the rest. Great for if you just really want to nail the freezing of the subject and don’t worry much about the surroundings.
Shutter speeds on many cameras can range from 1/8000th of a second (dang that’s quick!) down to 1 or 2 seconds, or even longer – typically up to 30 seconds. There’s another option usually called Bulb (or B) which means you determine how long the shutter is open for – usually controlled by a remote, or just keeping your finger pressed on the release button. Remember – shaky hands can cause shaky pictures.
In the below example, a fast shutter speed captured the spinny thing in sharp detail. As the shutter speed was elongated, the blur started to kick in.
For night photography, you may want to have a longer shutter speed to capture star trails, or to allow more light to come into your camera to light up the scene. On lakes, rivers, or the ocean, using a longer shutter speed will smooth out the water as it runs by.
In a crowded area, a 1 second shutter speed may show blurry people but keep buildings and other static objects sharp.
Of course, photography is purely subjective to what the photographer wants to show the viewer. The only technical aspects are just choices. No right or wrong.