Photography Myths: Part 1

Myths:
“I can take photos hand-held at 1/30th second!”
“To ensure sharpness, shoot at the reciprocal of your focal length; i.e. 1/200th second for a 200mm lens.”
“When shooting action, use a fast shutter speed to freeze the motion.”

Truth: You probably don’t look close enough to see how much sharpness is lost to camera motion blur, and the reciprocal rule’s value can vary dramatically from individual to individual. When taking action photos, using a shutter speed that’s too fast can ruin your picture.
Taming motion blur is actually one of the easiest ways to improve the sharpness of your images, and also the one that’s easiest to neglect. Photographers upgrade to higher-resolution cameras to get better photos, buy the best-quality lenses to converge the sharpest possible images onto the sensor, and focus with utmost precision, only to lose detail to motion blur. Some even brag that they are able to capture images handheld at remarkably low shutter speeds, not realizing that those shots at 1/15th second, while acceptable, aren’t as good as they might have been. Taking and partially releasing deep breaths, special bracing techniques, and a gentle finger on the shutter release can help, but they can’t replace other methods for reducing camera motion, and, of course, do nothing at all when your subject is moving faster than your shutter speed can freeze.
Subject motion is one sharpness-robber that has an easy set of cures, assuming that you want to freeze the action. Either reduce the apparent speed of your subject relative to your frame (e.g. pan, or have the subject moving toward you) or increase the shutter speed sufficiently to stop the motion. Most digital SLRs have shutter speeds of at least 1/4000th second; some top out at 1/8000th second. Either speed should be enough to stop virtually any action this side of a speeding bullet. Your only challenge is making sure you have enough light to allow using one of these tiny time slices at a reasonable ISO setting. When the available light is insufficient, electronic flash units have even more action-stopping power; the duration of some of them can be 1/50,000th second or briefer.
But don’t over-use fast shutter speeds. We’ve all seen photos of race cars or motorbikes that appear to be parked and immobile on the highway, or helicopters that seem to be on the verge of crashing because their rotors are stopped in mid-spin. Part of the creativity of action photography comes from experimenting to find a shutter speed that will allow wheels, propellers, and rocks kicked up by a speeding vehicle to blur realistically.
Blur caused by the camera, however, is almost always a bad thing. There are many elements involved other than the photographer’s shaky hand, too. Some recent cameras have added so-called electronic shutters that eliminate the blur caused by the camera’s front/first shutter curtain opening at the beginning of an exposure. Mirror lockup and delayed shutter features can help prevent internal vibrations that can affect both hand-held and tripod-mounted photography. Image stabilization can shift the position of the sensor or elements within the lens (or the pixels of the image itself in the case of electronic stabilization) to counter camera motion.
But the primary cause of camera motion blur still resides in the hands of the photographer. Most people find to their astonishment that, in a formal test and under close examination, their handheld photos with wide-angle or normal lenses at 1/500th second are significantly sharper than those taken at 1/125th second. Those they snap off at 1/30th second aren’t nearly as tack sharp as they’d been boasting when you peep the pixels. What looks pretty good at normal enlargement and viewing distances turns out to be not so good when you isolate your subject matter so the blur can be seen more easily, and examine the results up close. If you’re truly committed to raising the bar on your image quality, you might be making some changes in how you shoot after you try my sure-fire blur tester to see for yourself.
The first step is to build yourself a blur tester. I like to use a large piece of aluminum. You can use a scrap panel of aluminum, sacrifice a cookie sheet, or use a serving tray like I did. Take the sheet and poke a series of tiny pinholes in it, as perfectly round as you can make them. Although the size of the holes isn’t crucial, smaller is better; anything one-eighth inch or smaller should work. The most important thing is to have clean, perfectly round holes so you’ll be able to detect any deformation caused by camera shake.
Array the holes in a pattern resembling a plus sign, with intersecting vertical and horizontal arms. In a pinch you can use aluminum foil, although it’s more difficult to create perfectly round holes in foil because it tends to tear. If necessary, file way any burrs that result when you poke through the sheet. Remember, you want nice circular holes.
If you want to get fancy, you can spray paint the sheet with flat black paint to increase the contrast between the sheet itself and the light coming through the holes. After the paint dries, clean out any paint that goes into the holes. Painting is not really necessary if you conduct the test in a darkened room. Now you’re ready for your test.

  1. Mount the sheet vertically, perpendicular to the ground
  2. Point a strong light at the back of the sheet, illuminating the pinholes. Make sure no light spills over beyond the sheet itself, as excess light could cause flare in the test shots.
    Position yourself far enough from the sheet that you can fill the frame with the sheet.
  3. Focus very carefully on the sheet, using manual focus. Your autofocus system might not work well in this situation. Use the pinpoints of light as your focus point, and turn the focus ring until the points are as sharp as possible.
  4. Take a few shots using manual exposure until you find out which f-stop will give you a good exposure. Try to use f/8 to f/11 so your lens will be at a relatively sharp aperture. Although exposure isn’t super critical, you don’t want to overexpose and cause the pinholes to enlarge too much from blooming. You want tight, round dots of light.
  5. Take several pictures at each shutter speed you want to test.
  6. When you’re done, examine your shots. As you reduce the shutter speed, you’ll probably notice that the pin circles become elongated in the vertical, horizontal, or diagonal directions, depending on the bias of your shakiness. At worst, you may notice little wavering trails of light that show you’re not merely shaking a bit, but positively quivering.

The shape of the holes that you photograph will reveal the amount of camera shake at any tested shutter speed. Sometimes, just making a few adjustments in how you take pictures can help reduce camera shake. The biggest and most common offense is punching the shutter release. Beginners do this all the time as a matter of course; I’ve taken a photo with a simple point-and-shoot camera, handed the camera to a friend who then fired off a shot using the same settings. My picture turned out relatively sharp, while the friend’s was egregiously blurry. I’m no paragon of hand-holding steadiness, but I know enough to wait until the camera has stopped moving when I bring it to my eye, and then squeeze off a shot gently.

I’ve seen amateurs flip their camera up and shoot in a single motion. Because some cameras don’t have an eye-level viewfinder, they may hold the camera at arm’s length to frame using the LCD. That’s a perfect recipe for camera shake! Yet, even more experienced photographers are prone to bad shooting habits like these when they’re in a hurry or a photo opportunity presents itself without warning. Impromptu grab shots are especially dangerous because you may not even have time to notice what shutter speed the camera is using before taking the photo.

Even the most careless among us are a bit more careful when we know the shutter speed is set to 1/60th second than when it’s 1/500th second. If you take an extra half-second before shooting, you can improve your odds of getting a sharp shot significantly. Modern cameras that lock focus and exposure when the shutter release is depressed halfway have actually helped improve sharpness, because more of us are now gently releasing the shutter after that initial half-press.

As you can see, the reason why the reciprocal rule should be used only as a starting point is that a usable hand-held shutter speed depends greatly on the intended use for an image, and the photographer’s technique. You’re probably better off reducing the recommended speed – use 1/200th second with a 100mm lens, or 1/2000th second with a front-heavy 500mm telephoto lens – and even then consider using a tripod.

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