TECHtata

In Motion!

Ryan Brenizer

In a literal sense, pictures are static. Oh sure, the eyes on that wall-mounted portrait may seem to follow you around the room, but unless you're hanging out with Harry Potter, it's probably just an illusion.

Of course, there's a problem here. Yes, you can create great art by taking a six-hour exposure of a pepper, but there's more to the world than that. This is a world of motion, of running, jumping, dancing, playing, laughing, splashing, falling, and more gerunds than you could shake a stick at (it's also a world of shaking sticks). How, then, do you translate motion onto a still image?

The answers are as divergent as there are pictures, but for this week's TECHtata project, we'll focus on two broad methods: Stopping Time and Motion Blur.

These are pretty much the two diametrically opposed ways to capture a moving image, and yet, done correctly, they can both powerfully show the essence of motion. It all comes down to shutter speed -- in the first two images in the sidebar, the second was captured in an exposure about 67 times as long as the first.

Stopping Time means using a fast shutter speed to create an image that's tack sharp or nearly so. The best way this can show motion is to use the fast shutter possibilities of most cameras (1/16000th of a second on models like the Canon 1D or Nikon D2HS, and a perfectly useful 1/1000th even on most pocket cameras) on subjects that are moving too quickly for the human eye to see clearly. For example, Stopping Time on a ball rolling down a hill is probably not the best way to show motion, since everybody knows what a stationary ball looks like. They don't see people hanging in the air, strands of hair hanging motionless about their face very often, though.

Advanced versions of stopping time include multiple exposures, showing several copies of the same moving subject in one frame.

Motion Blur, in contrast, uses slow shutter speeds to show a subject as it exists in a visible range of time, all blurred together. Think of these images as viewing time somewhat like one of Vonnegut's Tralfamadorians would. The slow shutter creates an almost analog representation of memory, different than anything we see with out eyes, but recognizable when done correctly. It's important to remember that the shutter speeds do not have to be super-slow for this effect. Someone running will very nicely blurred by 1/15th of a second, whereas a 30-second exposure will render any moving subjects so blurry as to be nearly invisible.

This, dear Utatans, is a project than anyone with a camera can do. All cameras have shutter speeds. Many have direct shutter speed (S or, more obscurely, Tv). But even the most automatic cameras (other than some disposables) will vary their shutter speeds as the light changes. Want fast shutter speeds? Take pictures in sunlight. Want slow shutter speeds? Go into a dimly lit room (and, perhaps, turn on Night Portrait mode).

Advanced versions of this include using a rear-curtain sync flash, as discussed in the Flash TECHtata, to create one sharp image superimposed over the blur, or panning and zooming -- following your subject during the exposure to show motion by burring the world around it.

In this TECHtata project, we want Utatans to try both ways. Stopping Time images will be tagged "TECHtata04A" and Motion Blur images will be tagged "TECHtata04B". They don't have to be of the same subject or taken with the same camera even, they just have to be of the two types of motion capture. Let's get moving! And have fun!