Back to the Basics: Shutter Speed

Back to the Basics: Exposure, Part II: Last week, we discussed Aperture / F-stop.

Exposure is the capturing of an image on film or digital sensor through the use of light. Three factors go into making an exposure: Aperture, Shutter Speed and ISO. Changing one of those factors will effect your exposure AND one or both of the other two factors.

Shutter Speed

The location (and type) of the shutter will vary, depending on the type of camera. This diagram is true for most Single Lens Reflex (SLR) cameras.

What is the Shutter?
The shutter is a thin device in the camera or lens that shields the digital sensor / film from light. This device can be retracted to allow light to reach the sensor / film. When that happens, it’s called opening the shutter. The shutter must be open to make an exposure (take a photograph).

What is Shutter Speed?

Shutter speed determines the amount of time that the shutter is open. The shutter speed is a setting on the camera or lens. If you’re using a manual camera, then it’s probably on a dial on the top of the camera body. On digital SLR’s, there is typically an LCD screen that displays the shutter speed.

The LCD screen on a digital SLR shows the Shutter Speed to be set at 1/60th of a second.

The Shutter Speed dial of a manual camera, shows the shutter speed set to 1/60th of a second.

How is Shutter Speed Measured?

Shutter speed is measured in fractions of seconds (and seconds, when you get into longer exposures). It is usually abbreviated. A shutter speed of 1/60th of a second is generally written simply as 60. When a shutter speed is set for 1 second or more, it’s commonly written 1″, 2″, 3″, etc.

As with Aperture, from one shutter speed to the next, the time is halved or doubled. Longer shutter speeds allow more light to reach the sensor / film. Shorter shutter speeds allow less light. 1/30th of a second is a longer shutter speed than 1/500th because it’s a greater amount of time.

In addition to the numbers, your shutter speed may also have B and T settings. B stands for Bulb. With a bulb exposure, the shutter stays open as long as the shutter button is pressed. T is for Time. In a Time exposure, the shutter opens when the shutter button is depressed and remains open until the button is pressed a second time. These settings enable the photographer to take exposures longer than the camera’s (or lens’) longest shutter speed setting.

Currently, the fastest shutter speed available in digital cameras is 1/8000. A camera that has 1/8000 probably also has a 30″.

How do you open the shutter?

To open the shutter, press the shutter button (the button pressed to take a photo). The shutter will remain open for the duration of the shutter speed.

That covers the basics of Shutter Speed. Now, let’s look at how to choose the right shutter speed for your photograph.

Shot at 1/3200 to freeze the flow of water.

There’s really no best shutter speed. But, by thinking about what you’re shooting, you can narrow down your choices. Chose your shutter speed based on your subject matter and what you want your photograph to look like.

Reasons for using Faster Shutter Speeds
- Freezing action – use a fast speed to freeze motion.
- Shooting in a bright light situation – use a fast speed to reduce the amount of time that light is hitting the sensor / film.
- Hand holding the camera – The longer the exposure, the more difficult it is to hand hold a camera steady. A good rule of thumb is to hand hold at 1/60 and faster. When shooting slower than 1/60, it’s best to use a tripod.

Shot at 3.2 sec to capture motion blur.

Reasons for using Slower Shutter Speeds
- Motion blur – use a slower speed to blur moving water, cars, people, etc.
- Panning with motion – Panning is when the photographer moves the camera in pace with the action. This will freeze the motion and blur whatever was still.
- Low light situation – capture what little light there is by exposing the sensor / film for a longer period of time.

Next week, we’ll discuss ISO, the third factor in the Exposure Triangle. THEN, we’ll be ready to see how these three elements work together!

Additional Reading:

Back to the Basics: Aperture / F-stop

Back to the Basics: Aperture / F-stop part 2


Back to the Basics: ISO


Back to the Basics: Exposure Triangle