When To Use Shutter Priority Tv Mode

• When working with fast-moving subjects where you want to freeze the action (Figure 3.3); there is much more on this in Chapter 6

• When you want to emphasize movement in your subject with motion blur (Figure 3.4)

• When you want to create that silky-looking water in a waterfall or stream (Figure 3.5)

50mm lens

50mm lens

FIGURE 3.3

To freeze the laptop mid-air and reduce motion blur, I used a very fast shutter speed to photograph this image.

FIGURE 3.3

To freeze the laptop mid-air and reduce motion blur, I used a very fast shutter speed to photograph this image.

10-20mm lens

10-20mm lens

FIGURE 3.4

A slow shutter speed was used to emphasize the movement of the biker.

FIGURE 3.4

A slow shutter speed was used to emphasize the movement of the biker.

FIGURE 3.5

I used a slow shutter speed to blur the motion of the water in the stream and give it a softer look.

FIGURE 3.5

I used a slow shutter speed to blur the motion of the water in the stream and give it a softer look.

ISO 100 28 sec. f/22

10-20mm lens

As you can see, the subject of your photo usually determines whether or not you will use Tv 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 checking your shot on the LCD screen. But what if you only have one chance to catch the shot? Such is often the case when shooting sporting events. It's not like you can go ask the quarterback to throw that winning 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 7D has a shutter speed range from 1/8000 of a second all the way up 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 Tv 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 the aperture display in your viewfinder and on the top LCD panel will begin to blink. 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 that blinking aperture display once again 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 5), but it is important to know that there can be limitations when using Tv mode.

SETTING UP AND SHOOTING IN TV MODE

1. Turn your camera on and then turn the Mode dial to align the Tv with the indicator line.

2. Select your ISO by pressing the ISO button on the top of the camera and then turning the Main dial (the ISO selection will appear in the top LCD Panel).

3. Point the camera at your subject and then activate the camera meter by depressing the Shutter button halfway.

4. View the exposure information in the bottom area of the viewfinder or by looking at the top LCD Panel.

5. While the meter is activated, use your index finger to roll the Main 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.

SHUTTER SPEEDS

A slow shutter speed refers to leaving the shutter open for a long period of time—like 1/30 of a second or longer. A fast shutter speed means that the shutter is open for a very short period of time—like 1/250 of a second or less.

IMAGE STABILIZATION LENSES

Some Canon lenses come with a feature called Image Stabilization (IS) (Figure 3.6). It's a mechanism that's built directly into the lens and helps reduce motion blur due to camera shake when photographing at slower shutter speeds.

If you have this option on your lens, it's a good idea to leave it turned on when doing any handheld photography. Because the IS mechanism in the lens moves when turned on, you'll want to turn it off when using a tripod. It could introduce camera shake in your images if the camera is perfectly still on a tripod, so it is typically only recommended for handheld photography.

FIGURE 3.6
100 Photography Tips

100 Photography Tips

To begin with your career in photography at the right path, you need to gather more information about it first. Gathering information would provide you guidance on the right steps that you need to take. Researching can be done through the internet, talking to professional photographers, as well as reading some books about the subject. Get all the tips from the pros within this photography ebook.

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