Section 2.7. Stop the Action

2.7. Stop the Action

Although some blurring can be effective in communicating a sense of high-speed motion, most of the time you want your subject frozen in time, especially if you're shooting high-speed action such as sporting events or car races. The other problem that goes right along with freezing the action is managing to catch the most expressive instant that lasts for only hundredths of a second.

7.1. High Shutter Speed Considerations

The first thing you need to know is just how brief your exposure must be to stop the action. You also need to know that the required shutter speed will increase with the angle at which the subject is approaching or going away from the camera. It is easier to freeze the action of a cyclist who's heading straight toward you than one who is passing perpendicular to you.

You also have to consider how much of the subject you want to freeze. For instance, the legs of a running horse or the wings of a flying bird are moving much faster than the body. So you have to decide whether you want the subject completely frozen or whether the blurred movement of some limbs or other parts simply makes the subject look like it's moving faster. A photograph of a flying airplane with frozen propeller blades will simply make you think the plane is about to crash.

7.2. Panning with the Subject

If the subject is moving perpendicular to the camera's line of sight, you can often keep the subject sharpeven at relatively slow shutter speedsby panning. Panning is lensman-speak for rotating the camera on a pivot point. The pivot point is usually the tripod thread. However, if you're hand-holding the camera, you just have to pretend there's a pivot point under the camera. The cyclist in Figure 2-13 was shot at a shutter speed of 1/30th of a second while the camera's spot metering point was centered on the tip of the seat. For a different subject, just find any point that is at the center of the subject and at the same distance from the camera as the main body of the subject.

Figure 2-13. A cyclist shot at 1/30th of a second while panning.

When I was shooting the cyclist, the camera was set in sequence mode so that the camera fired several shots as it was panned. I then threw away all but the steadiest shot. If you don't have a sequence mode (or weren't thinking ahead), just try to shoot several shots of a similar subject. Of course, if the subject is Lance Armstrong, you'd better think ahead. You may have only one chance.

7.3. Shooting Sequences

Some Nikon cameras have a setting called Best Shot mode. Best Shot mode lets you fire a sequence and then automatically throws away all but the sharpest image. Whoever thought of it was a genius. However, I'm guessing that Nikon patented the idea, so you'll just have to do the next best thing. When you have to hand-hold for the steadiest possible shot, follow the appropriate recommendations above. Then put the camera in sequence mode, and when you've got the camera as steady as possible, shoot a sequence. If you don't have time during the shoot to kill the blurry shots, don't worry. You can do it better when you can enlarge them on your computer (preferably in Camera Raw).

7.4. The Electronic Flash Advantage

One of the advantages of shooting in a studio is that you will likely use an electronic flash as the lighting source. Since electronic flash (aka strobe) stays lit between 1/800th and 1/2000th of a second, and because you will usually be shooting at f-stops above f-8, everything in the image is razor sharp. If you need to shoot a photo of a girl's hair flying or freeze the splash of a pouring drink, strobe is the way to do it.

Usually, you will want to use strobe to stop action when there is no other lighting source. That is because the camera (with few exceptions) has to use a shutter speed of about 1/125th of a second to synchronize properly with the flash. However, there's a very nice effect to be had for some subjects when you balance the lighting so that about half the brightness comes from the strobe and the other half from ambient light. Move the subject fast enough to blur at the shutter speed you're using. The subject will be razor sharp at the instant the flash is fired and, especially if you use a slow enough shutter speed, very blurry for the time leading in and out of the moment the flash is fired. You can see an example of this in Figure 2-14.

Figure 2-14. Using a combination of strobe and continuous lighting can lead to an effect similar to the one seen here.

2.7.5. The Fast Lens Advantage

If you're just getting into using professional DSLRs, you are probably smart enough to buy your first one with a "kit" lens or two. After all, if you don't have any lenses to go with the camera, you might as well save a few hundred dollars by investing in a starter kit. Most of those I've tested have been very worthwhile bargains (please don't interpret this to mean that they are the best optics money can buy, however). There's one thing they lack, though: an ultra-wide aperture that lets you shoot in low light or easily throw distracting backgrounds out-of focus.