S: Shutter Priority Mode
S mode is what we photographers commonly refer to as Shutter Priority mode. Just as the name implies, it is the mode that prioritizes or places major emphasis on the shutter speed above all other camera settings.
Just as with Program mode, Shutter Priority mode gives us more freedom to control certain aspects of our photography. In this case, we are talking about shutter speed. The selected shutter speed determines just how long you expose your camera's sensor to light. The longer it remains open, the more time your sensor has to gather light. The shutter speed also, to a large degree, determines how sharp your photographs are. This is different from the image being sharply in focus. Two of the major influences on the sharpness of an image are camera shake and the subject's movement. Because a slower shutter speed means that light from your subject is hitting the sensor for a longer period of time, any movement by you or your subject will show up in your photos as blur.
When to Use Shutter Priority (S) Mode
- When working with fast-moving subjects where you want to freeze the action (Figure 4.3); much more on this is in Chapter 5
Figure 4.3 Even the fastest of subjects can be frozen with the right shutter speed.
- When you want to emphasize movement in your subject with motion blur (Figure 4.4)
Figure 4.4 Slowing down the shutter speed and following the motion conveys a sense of movement in the shot.
- When you want to use a long exposure to gather light over a long period of time (Figure 4.5); more on this is in Chapter 8
Figure 4.5 Long exposure coupled with a steady tripod capture a portrait of our pet scorpion under a single blacklight bulb.
- When you want to create that silky-looking water in a waterfall (Figure 4.6)
Figure 4.6 Increasing the length of the exposure time gives falling water a silky look.
As you can see, the subject of your photo usually determines whether or not you will use Shutter Priority mode. It is important that you be able to visualize the result of using a particular shutter speed. The great thing about shooting with digital cameras is that you get instant feedback by viewing your shot on the LCD screen. But what if your subject won't give you a do-over? Such is often the case when shooting sporting events. It's not like you can go ask the quarterback to throw that touchdown pass again because your last shot was blurry from a slow shutter speed. This is why it's important to know what those speeds represent in terms of their capabilities to stop the action and deliver a blur-free shot.
First, let's examine just how much control you have over the shutter speeds. The D5100 has a shutter speed range from 1/4000 of a second all the way down to 30 seconds. With that much latitude, you should have enough control to capture almost any subject. The other thing to think about is that Shutter Priority mode is considered a "semiautomatic" mode. This means that you are taking control over one aspect of the total exposure while the camera handles the other. In this instance, you are controlling the shutter speed and the camera is controlling the aperture. This is important, because there will be times that you want to use a particular shutter speed but your lens won't be able to accommodate your request.
For example, you might encounter this problem when shooting in low-light situations: If you are shooting a fast-moving subject that will blur at a shutter speed slower than 1/125 of a second but your lens's largest aperture is f/3.5, you might find that your aperture display in the viewfinder and the rear LCD panel will display the word "Lo." This is your warning that there won't be enough light available for the shot—due to the limitations of the lens—so your picture will be underexposed.
Another case where you might run into this situation is when you are shooting moving water. To get that look of silky, flowing water, it's usually necessary to use a shutter speed of at least 1/15 of a second. If your waterfall is in full sunlight, you may get a message that reads "Hi" because the lens you are using only stops down to f/22 at its smallest opening. In this instance, your camera is warning you that you will be overexposing your image. There are workarounds for these problems, which we will discuss later (see Chapter 7), but it is important to know that there can be limitations when using Shutter Priority mode.
Setting Up and Shooting in Shutter Priority Mode
- Turn your camera on and then turn the Mode dial to align the S with the indicator line.
- Select your ISO by pressing the i button on the back of the camera.
- Press up or down on the Multi-selector to highlight the ISO option and then press OK.
- Press down on the Multi-selector to select a higher ISO setting, then press OK to lock in the change.
- Point the camera at your subject and then activate the camera meter by depressing the shutter button halfway.
- View the exposure information in the bottom area of the viewfinder or by looking at the rear LCD panel.
- While the meter is activated, use your thumb to roll the Command dial left and right to see the changed exposure values. Roll the dial to the right for faster shutter speeds and to the left for slower speeds.