In this lesson: Explore how to use Tv or S mode to let the camera adjust exposure

Your camera’s autoexposure system can be used in situations that call for fast shutter speeds to stop motion or slow shutter speeds to blur motion. By using shutter priority mode, you can select the desired shutter speed while allowing the camera to set the appropriate aperture setting. The result is a well-exposed image that still has the desired motion effects.

Allowing the camera to adjust the exposure of your images can help capture the right moments. Shutter priority mode, indicated by Tv on Canon cameras and S on Nikon cameras, is a good choice for this because you set a shutter to either stop or blur motion, and the camera selects the correct aperture setting to maintain a good exposure. By selecting an appropriate ISO setting beforehand, you can simply make one adjustment (to the shutter speed) as necessary, and changing light conditions won’t cause exposure errors.

For example, in the primary image above, the photographer selected a shutter speed that was slow enough to allow for the creation of light trails in the image. The aperture selected by the camera allowed for a well-exposed image as well. Note how each element in the photo – from the cars in the foreground to the buildings in the background, is nicely exposed with no areas that are too dark or too bright.

Shooting in shutter priority mode offers the following advantages:

• Stop action when shooting moving subjects: If your subject is on the move, as is the case in the image above, shutter priority mode allows you to more easily freeze movement because you’re in control of the shutter speed being used. Note how the impression of movement is still there – it’s obvious that the man is lifting and spinning the boy around – but their movement, for the most part, is frozen because of the use of a fast shutter speed.

• • Creative control of motion blur: Shutter priority mode also allows you to blur movement, if you desire. Just select a slower shutter speed to induce blur, and the camera will adjust the aperture accordingly.

• Ensure the best performance when shooting in continuous mode: When the action is really fast, shooting in continuous mode gives you a greater ability to capture that perfect moment. Doing so in shutter priority mode also means that your images will have the desired motion effect as well.

• Automatic adjustment for changing light conditions: Again, because the camera selects the aperture on your behalf, you can concentrate on freezing or blurring motion as you see fit, with the comfort of knowing that the camera will automatically adjust the aperture to account for changing lighting conditions.

• Allows the photographer to concentrate more on the subjects: Because you don’t have to worry about setting the aperture, and because the camera will help you with getting the exposure just right, you have more time to concentrate on your subject. 

A Word of Warning

Remember that by giving the camera control of the aperture, you lose the ability to control depth of field. That makes this mode more suitable for situations in which controlling motion is the most important factor, either to freeze the subject or to add motion blur for creative effect.

For example, if you’re shooting a portrait, shutter priority mode would not be advisable because you wouldn’t be able to control depth of field – you might end up with a portrait in which the subject and the surroundings from foreground to background are all in sharp focus. However, shutter priority mode is ideal for situations in which the subject is moving, like the train passing by in the image above. A slow shutter speed allowed the photographer to blur the motion of the fast-moving train, yet, because the man is stationary, he appears sharp with no indication of movement.

Challenge Activity

In this challenge activity, you will tackle the process of using shutter priority mode. Take a series of photos of fast-moving objects, using shutter priority mode on your camera. Set the appropriate ISO settings and shutter speeds to control the motion in the shots, allowing the camera to adjust the exposure via the aperture setting.

Step 1: With your camera mounted on a tripod, position yourself safely along a sidewalk facing a busy street.

Step 2: Set your shutter speed at or above 1/500 second at an ISO setting of 400 or higher.

Step 3: As vehicles pass by, take a series of photos, stopping and blurring their motion by raising or lowering the shutter speed. Note with each adjustment of the shutter speed how the impression of movement is impacted. Then, once you’re comfortable using shutter priority mode, find other subjects for similar experiments with freezing or blurring motion. Possibilities include people playing sports, animals running, and the movement of water.