Capturing Motion with Your Canon EOS 7D Mark II
Stop Right There!
Shutter speed is the main tool in the photographer’s arsenal for capturing great action shots. The ability to freeze a moment in time often makes the difference between a good shot and a great one. To take advantage of this concept, you should have a good grasp of the relationship between shutter speed and movement. When you press the shutter release button, your camera goes into action by opening the shutter curtain and then closing it after a predetermined length of time. The longer you leave your shutter open, the longer your subject will appear within the frame, so common sense dictates that the first thing to consider is just how fast your subject is moving.
Typically, you will be working in fractions of a second. How many fractions depends on several factors. Subject movement, though simple in concept, is actually based on three factors. The first is the direction of travel. Is the subject moving across your field of view (left to right) or traveling toward or away from you? The second consideration is the actual speed at which the subject is moving. There is a big difference between a moving sports car and a child on a bicycle. Finally, the distance from you to the subject has a direct bearing on how fast the action seems to be taking place. Let’s take a brief look at each of these factors to see how they might affect your shooting.
Direction of travel
Typically, the first thing that people think about when taking an action shot is how fast the subject is moving, but in reality the first consideration should be the direction of travel. Where you are positioned in relation to the subject’s direction of travel is critically important in selecting the proper shutter speed. When you open your shutter, the lens gathers light from your subject and records it on the camera sensor. If the subject is moving across your viewfinder, you need a faster shutter speed to keep that lateral movement from being recorded as a streak across your image. Subjects that are moving perpendicular to your shooting location do not move across your viewfinder and appear to be more stationary. This allows you to use a slightly slower shutter speed (Figure 4.1). A subject that is moving in a diagonal direction—both across the frame and toward or away from you—requires a shutter speed in between the two.
Figure 4.1 Action coming toward the camera can be captured with slower shutter speeds.
ISO 400 • 1/1000 sec. • f/4 • 300mm lens
Once the angle of motion has been determined, you can then assess the speed at which the subject is traveling. The faster your subject moves, the faster your shutter speed needs to be in order to “freeze” that subject (Figure 4.2). A person walking across your frame might only require a shutter speed of 1/60 of a second, whereas a cyclist traveling in the same direction would require 1/500 of a second or faster. That same cyclist traveling toward you at the same rate of speed, rather than across the frame, might only require a shutter speed of 1/250 of a second. You can start to see how the relationship of speed and direction comes into play in your decision-making process.
Figure 4.2 A fast-moving subject that is crossing your path will require a faster shutter speed.
ISO 640 • 1/2000 sec. • f/2.8 • 300mm lens
So now you know both the direction and the speed of your subject. The final factor to address is the distance between you and the action. Picture yourself looking at a highway full of cars from up in a tall building a quarter of a mile from the road. As you stare down at the traffic moving along at 55-plus miles per hour, the cars and trucks seem to be slowly moving along the roadway. Now imagine yourself standing in the median of that same road as the same traffic flies by.
Although the traffic is moving at the same speed, the shorter distance between you and the traffic makes the cars seem like they are moving much faster. This is because your field of view is much narrower; therefore, the subjects are not going to present themselves within your field of view for the same length of time. The concept of distance applies to the length of your lens as well (Figure 4.3). If you are using a wide-angle lens, you can probably get away with a slower shutter speed than if you were using a tele-photo, which puts you in the heart of the action. It all has to do with your field of view. That telephoto gets you “closer” to the action—and the closer you are, the faster your subject will be moving across your viewfinder.
Figure 4.3 Due to the distance from the camera, a slower shutter speed could be used to capture this action.
ISO 100 • 1/400 sec. • f/14 • 300mm len
A Sense of Motion
Shooting action isn’t always about freezing the action. There are times when you want to convey a sense of motion so that the viewer can get a feel for the movement and flow of an event. Two techniques you can use to achieve this effect are panning and motion blur.
Panning has been used for decades to capture the speed of a moving object as it moves across the frame. It doesn’t work well for subjects that are moving toward or away from you. Panning is achieved by following your subject across your frame, moving your camera along with the subject, and using a slower-than-normal shutter speed so that the background (and sometimes even a bit of the subject) has a sideways blur, but the main portion of your subject is sharp and blur-free. The key to a great panning shot is selecting the right shutter speed: too fast and you won’t get the desired blurring of the background; too slow and the subject will have too much blur and will not be recognizable. Practice the technique until you can achieve a smooth motion with your camera that follows along with your subject. I usually begin around 1/30 of a second, and then make changes depending on the results. The other thing to remember when panning is to follow through even after the shutter has closed. This will keep the motion smooth and give you better images.
In Figure 4.11, I used the panning technique to follow this motocross rider as he rode in front of me. I set the camera drive mode to Continuous shooting, and I used Tv mode to select a shutter speed of 1/40 of a second while the focus mode was on AI Servo. It’s important to shoot a continuous sequence, because you are more likely to get at least one good frame from the burst.
Figure 4.11 Following the subject as it moves across the field of view allows for a slower shutter speed and adds a sense of motion to the shot.
ISO 2000 • 1/40 sec. • f/9 • 116mm lens
Another way to let the viewer in on the feel of the action is to include some blur in the image. I don’t mean accidental blur from choosing the wrong shutter speed. This blur is more exaggerated, and it tells a story. In Figure 4.12, I was interested in capturing the movement of the kayaker as he paddled through the fast-moving water. A fast shutter speed would have surely frozen the action, but it would not have told the story of the movement. Instead of moving with the action, I let the movement of the kayaker and the water create the blur as I held the camera in a stationary position.
Figure 4.12 The movement of the water and kayaker, along with a slow shutter speed, helps to convey the action.
ISO 100 • 1/20 sec. • f/25 • 185mm len
Just as in panning, there is no preordained shutter speed to use for this effect. It is a matter of trial and error until you have a look that conveys the action. I usually try to get some area of the subject that is frozen. The key to this technique is the correct shutter speed combined with keeping the camera still during the exposure. You are trying to capture the motion of the subject, not the photographer or the camera, so use a good shooting stance or even a tripod. Also, try shooting in Continuous drive mode and capture several consecutive exposures. Chances are, your first one may not look good, but one of the images in the series will have just the look you are after.