On Photography
By Robert de Gast, Feb 9, 2007

No great shakes!

The pictures that disappoint most often, technically speaking, are usually those that exhibit “camera shake,” the blurry, unsharp look that results from the movement of the camera when using slow shutter speeds. A shutter speed is defined as the length of time that the “curtain” is opened to let light fall on the film (or the digital sensor). Naturally, 1/500th of a second with a hand-held camera will produce a sharper picture than one made at, say, 1/10th of a second. But we can’t always have those higher speeds, usually because of low light levels. And as long as blood is coursing through your body you will transmit motion to your camera, often with annoying and disappointing results.

Recently, I worked with a student who had just returned from an African wildlife safari. Before leaving for this journey he had bought a digital camera with an enormous (10×) zoom lens. This, of course, made sense, since you want to keep a respectable, telephoto distance from assorted lions and other dangerous creatures. My student shot hundreds of pictures, but upon close examination he found that none was sharp enough to merit enlargement. Camera shake! Even at the Auto setting the camera could not come up with the higher shutter speeds required to ensure razor-sharp images. What could he have done?

To begin with, he could have checked the shutter speed he used. This is always indicated on the LCD screen on the back of the camera or the control panel on the top.

If you play back the image you can also access the meta-data, which will tell you, among lots of other information, what shutter speed was used.

To prevent blurring caused by camera shake, as a rule of thumb the shutter speed should be faster than the inverse of the focal length of the lens, in seconds (in plain English, if, for example, the lens you are using has a focal length of 300 mm, the shutter speed should be faster than 1/300 second. If you are using a 28-mm lens you are in good shape if you’re using a shutter speed faster than 1/28 second. I know, there is no 1/28, but this is not rocket science, and 1/30 or faster would solve the problem).

My student was using a 400-mm lens and should never have tried to hand-hold his camera at less than 1/400 of a second.

If there is not enough light to attain those higher shutter speeds, increase the ISO (the sensitivity) of the camera, something that most digital cameras will allow. Go from the default (often 100 or 200 ISO) to 400, 800 or higher. Be aware, though, that so-called “noise” (pixel anomalies) will likely increase. There is, to be sure, no such thing as a free lunch.

A tripod, of course, can be of great help, but we’re often in situations that do not lend themselves to that sort of solution. A monopod can sometimes solve the problem, as can a bean bag or just bracing yourself against a solid structure.

Fortunately, many cameras now offer “image stabilization.” With image stabilization, either the camera or lens has moving elements to compensate for camera movement at slow shutter speeds. It is not a panacea. At best, this nifty technology can give you two or three faster shutter speeds.

If you have an SLR, you can buy VR (Vibration Reduction) lenses from Nikon, IS (Image Stabilizer) lenses from Canon and OS (Optical Stabilizer) lenses from Sigma. Konica Minolta’s SLR has an AS (Anti-Shake) system that moves the sensor to respond to camera shake, so every lens acts like it has stabilization built into it.

According to Dave Pahl, who works for the Digital Camera Solutions Unit at Texas Instruments, “For those of you who haven’t spent the few thousand dollars for today’s SLR image stabilized lenses, you’re in for a pleasant surprise—you won’t need to. You’ll be seeing chip-based image stabilization technology on affordable point-and-shoot cameras in the near future.” The future is here already: Nikon and Canon use optical adjustments inside their cameras, the Coolpix 8800 and PowerShot SI IS, respectively, while Konica Minolta uses a moving sensor in the DiMAGE A series of cameras.

Slow and steady may win the race, but fast and steady makes for sharp memories.

Robert de Gast, a long-time resident of San Miguel, has been a magazine photographer for nearly 50 years. He lectures and offers short photography tutorials. He can be reached at 152-7396 or by email at robertdegast@hotmail.com.