Shooting Sequences

Whether you call it sequence shooting, burst mode, continuous advance, or "motor drive" mode, the ability to take multiple shots of fast-moving action is a valuable capability found in an increasing number of digital cameras. On the plus side, ripping off five or ten shots as the action unfolds can increase your chances of catching the peak moment(s) in one or more of them. Unfortunately, you can also end up with the best shot of all occurring between frames. Sequence shooting is a valuable tool, but it's not a panacea.

Back when I was shooting sports professionally, a motor drive for my Nikon was the first accessory I purchased after a 400mm lens. Digital "motor drives" are way cooler than the mechanical variety. The biggest problem with motor transport on a conventional camera was that, at, say, three frames per second, you could eat up an entire 36 exposure roll of film with fewer than a half dozen action sequences. Remember, film can't be erased and re-used if you point the camera and shoot a busted play. For the big time pros traveling around the world to cover a major sports event, film is likely to be the least expensive part of the cost equation, so special camera backs that could hold 33 or more feet of film and expose hundreds of images in one shoot became common.

Digital cameras bring sequence photography to the rest of us. There's no need to buy an expensive camera, special film back, or burn up hundreds of feet of film. Action sequences can be captured digitally, and if a particular sequence doesn't bear photographic fruit, it can be erased and the memory card re-used.

Sequence photography is no substitute for good timing, however. Once you've solved the shutter lag problem, so your camera cooperates by exposing a photograph reasonably soon after you press the shutter button, you'll find your best photographs come from your instincts. Clicking off a picture at exactly the right moment will almost always yield better results than blindly capturing a series of frames at random. Use your camera's sequence mode as a supplement to your customary techniques, to grab a few pictures you might not have gotten otherwise, or to create sequences that are interesting in themselves, as shown in Figure 5.35.

Figure 5.35. The best sequence shots are those in which the series itself tells a story.

You can see from the changing background that this series wasn't a simple motordrive sequence of images taken a split-second apart. Instead, I used the digital camera's multi-shot capabilities to take a series of photos as the athlete rounded the bases. Each of these photos was probably taken a few seconds apart, much more closely spaced than I'd have been able to shoot if I'd elected to whack the shutter button individually for each picture. Instead, I elected to let the camera take full-frame shots at a two-per-second rate while I panned and zoomed to follow the runner's progress. Each image tells something about the play, and you can almost see the excitement build on the player's face as he rounds third and heads for home.

Selecting Sequence Modes

Your digital camera probably has five or six "drive" modes, not all of which are useful for action photography. Some are better suited for special applications like time-lapse photography or making mini-movies, but here's a list of the most common modes:

• Single frame advance. In this mode, you can take one picture each time the shutter release is pressed. Your camera probably has enough internal buffer memory that you can take another picture immediately, even if the camera has not offloaded the picture you've just taken to the film card. If not, you'll have to wait until the blinking light (or other indicator) stops to shoot the next picture.
• Continuous advance. The camera continues to take photographs, one after another, for as long as you hold down the shutter button. Depending on your camera, the effective frame rate may be anywhere from one frame per second or slower to two or more frames per second. The number of frames you can take may be limited by the amount of internal memory your camera has, and certainly will be limited by the number of available exposures on your memory card. When the internal memory is full, you'll have to stop taking continuous shots and wait until some room opens up. This is the mode I used for Figure 5.36.

Figure 5.36. A sequence photo like this one has a lot more excitement than any single frame of the set taken alone.

• High-speed continuous advance. The camera takes pictures continuously as you hold down the shutter release, at a frame rate from 3 to 5 frames per second or more. As with ordinary continuous advance, once your camera's buffer memory is full, your sequence is over until some of the images are offloaded to your memory card.
• Ultra high-speed continuous advance. This mode usually supplies your camera's fastest frame rate, from 5 to 7 or more frames per second. Usually, the camera must use a reduced image size in this mode that's smaller than the maximum size your camera can produce. For example, you might have to shoot at 1600 x 1200 or 1280 x 960 pixel resolution in this extra-fast mode. Even the lofty Nikon D2X digital SLR must crop the image down to "only" 3216 x 2136 resolution (6.8 megapixels) from its maximum 4288 x 2848 resolution (12.4 megapixels) to achieve 8 frames per second.
• Multi-shot. A few cameras can produce a quick blast of 16 tiny pictures on a single frame. Such images might be okay for analyzing your golf stroke, but may be too small for other applications.
• Mini-movie. Most non-dSLR digital cameras have the ability to shoot short video clips (typically 20-30 seconds) at 320 x 200 to 640 x 480 resolution (or higher). You can use the movies as is, or save and edit individual frames.
• Time lapse/interval. Although this is a sequence mode, it operates over a period that can extend for many, many seconds, and is best used for taking pictures of slow-moving events, such as the opening of a flower.
• Bracketing. In this mode, your camera takes several pictures in sequence, but uses different settings for each picture, improving your chances of getting one shot that has a better combination of settings. The most common bracketing procedure is to make several pictures at different exposures, with some underexposed and some overexposed (based on the meter reading). Many digital cameras can bracket other features, such as color correction, color saturation, contrast, white balance, or special filters.

Of all the sequence modes, I prefer the basic continuous mode, and frequently trigger the sequence just before I expect some action to take place, as shown in Figure 5.36. This technique is still a hit-or-miss procedure, because a lot can happen between frames. It's very likely that you'll still miss the decisive moment, but I had that happen to me when I was using a three-frames-per-second motor drive, too. As with all sports photography, the more pictures you take, the more you increase your odds of getting some great ones.

Shooting Sequences

Each particular sequence mode has its own advantages and disadvantages. The more frames you capture per second, the quicker your digital film will fill up with images, so high frame rates must be balanced with how much storage space you have available. In addition, the resolution and compression ratio of the image may affect how quickly you can shoot and how many images may be captured in a sequence.

For example, with a typical 5MP camera like my Minolta, the number of photographs that can be taken in a single burst looks like the results in Table 5.1.

Table 5.1. Compression Ratio Size (in pixels)

	2560 x 1920	1600 x 1200	1280 x 960	640 x 480
RAW	5	0	0	0
Super Fine	3	3	3	3
Extra Fine	7	12	15	33
Fine	10	19	27	61
Standard	17	29	42	84

As you can see, bursts might be limited to as few as 3 to 5 in the uncompressed TIFF (Super Fine) and RAW modes, while you can get as many as 84 images if you use 640 x 480 resolution and high compression (Standard). I usually use full resolution and Extra Fine compression, because seven pictures in one burst is usually plenty for my sequences.

Your camera's ultra high-speed mode provides more frames per second, but might provide an automatic reduction in resolution. For example, some cameras switch to 1600 x 1200 or 1280 x 960 resolution for extra high frame rates, which can range from 7 to 10 fps or more. You probably won't be able to use RAW or uncompressed TIFF formats in this mode.

Another limitation of sequence shooting is that you won't be able to use your electronic flash in most cases. A flash must be specially designed for rapid-fire to work in this mode. Even then, you'll be limited to close-ups, because such flash operate on the principle that because close-up photos don't require the full charge of the flash, several briefer exposures are possible at faster intervals.

Once you've set up your camera, shooting sequences is relatively painless. Set focus and exposure as described earlier in this chapter. Frame your subject, and when the action that you want to capture begins, press the shutter release and hold it down. Usually you'll have to follow the subject by panning the camera, which can be tricky if your viewfinder doesn't provide a steady image to watch during the sequence. After you've finished shooting, review your sequence with an eye towards improving your shots on the next take.

Testing Your Camera's Sequence Capabilities

You might want to measure exactly how many frames your digital camera can shoot using its continuous advance feature. That XNote Stopwatch utility I mentioned earlier in this chapter is a perfect tool for measuring frame rates, both for individual, continuous shots, and in burst mode. You can test your camera using various file formats and compression ratios to see which is most suitable for your action photography. Follow the steps for the two methodologies that follow, and record your results.
To Measure Maximum Individual Shot Rate

To measure how quickly you can take individual photos, follow these steps:

1. Set your digital camera for minimal shutter lag using the recommendations from earlier in this chapter.
2. Load the stopwatch software, and start it running. The actual time setting when you begin shooting doesn't matter, so let it operate.
3. Focus the camera on the stopwatch on your computer screen.
4. Press the shutter release to take a picture of the stopwatch.
5. Keep pressing the shutter button to take multiple pictures.
6. Load all the photos into your computer and examine them in your image editor.
7. Subtract the stopwatch time shown in each shot from the one in the previous shot to determine the interval between shots.
8. Average the intervals to arrive at the number of shots you can take individually.

To Measure Continuous Sequences

You can also accurately measure the true frame rate of your camera when set in automatic continuous picture taking mode. Just follow these steps, and repeat at each image size your camera offers for sequence photography:

1. Set your digital camera to minimize shutter lag, as before.
2. Set the camera to shoot continuously when you hold down the shutter release.
3. Load the stopwatch software and focus your camera on the stopwatch image on the screen.
4. Start the stopwatch timer and press the shutter release at the same time.
5. Hold down the shutter release to take as many frames as possible.
6. Load the pictures you've taken into an image editor and calculate the elapsed time for the entire sequence.
7. Tabulate your results to learn the length of time you can cover with a single sequence of images, and the approximate number of frames per second. For instance, if your camera takes 14 images in 1.8 seconds before the internal memory fills, you'll know you can capture about 2 seconds worth of action at a rate of roughly 7.7 frames per second.