Two Ways to Freeze Action With Your Flash

Cameras love light. Unless you're standing outdoors at midday, the easiest way to take a good photo is generally to simply add light to the scene. That's the idea behind your camera's flash, as we've discussed before. This week, let's see how to combine the flash and slower shutter speeds for some less common photo situations.

Balance the Exposure With a Slow Shutter Speed

Ordinarily, your camera is programmed to fire the flash and then leave the shutter open for about 1/60 second. That's a formula that camera makers have stuck with for many decades. Sometimes, though, using the default setting results in an oasis of light in the foreground, set against a completely dark background, as if your subject is standing at the very entrance of Hades. It's times like this when a longer shutter speed can really hit the spot.

Consider a nighttime or low-light scene in which you're trying to illuminate both a person in the foreground and the more distant background. You probably already know that your camera's flash has a very limited range, so the flash won't reach the background. Here'a an example of a typical shot in the early evening with the flash firing in automatic mode.

What to do? The easiest solution is often to slow down the shutter speed, which gives the camera more time to expose light in the scene. Combine a slow shutter speed with the flash, and you have a winning combination.

For best results, I recommend switching your camera to manual exposure mode and dialing in a shutter speed between 1/2 and 1/30 second. The slower the shutter speed, the more illuminated the background will be. In this case, you probably don't need to worry too much about using a tripod. The flash will freeze the action in the foreground, and the background might blur a bit, but the effect is often attractive. Here's the same scene with a 1-second exposure.

Capture Light Trails and Motion

That technique is great for giving the background some definition. But we can make it even more interesting. Suppose you're taking a photo in low light in which there's some motion--such as car headlights or even people who are illuminated by a light source. You can get a really cool effect by extending the technique we just used. Shoot with a slow shutter speed to generate trails of light or motion in the scene, and also fire the flash to freeze the foreground action.

If you want to try this out, check out your camera's flash menu to see if it offers a setting called Rear Curtain Sync. This setting sounds a bit complicated, but all it really means is that when you use this setting, the flash fires at the end of the exposure rather than at the start. The difference is readily apparent in longer exposures. Check out this photo of my daughter walking under a street light.

In this photo, the flash fires right away--as it normally does, and the 1-second exposure captures wisps of her as she walks forward (especially near her head)--generating a somewhat unsettling image.

But if we switch the camera to Rear Curtain Sync mode, the flash fires at the end of the exposure, meaning that the wispy trails are behind her in the photo--a completely different effect.

Have fun experimenting on your own!

Hot Pic of the Week

Get published, get famous! Each week, we select our favorite reader-submitted photo based on creativity, originality, and technique.

Here's how to enter: Send us your photograph in JPEG format, at a resolution no higher than 640 by 480 pixels. Entries at higher resolutions will be immediately disqualified. If necessary, use an image editing program to reduce the file size of your image before e-mailing it to us. Include the title of your photo along with a short description and how you photographed it. Don't forget to send your name, e-mail address, and postal address. Before entering, please read the full description of the contest rules and regulations.

This week's Hot Pic: "Southwest Exposure" by Bob Estrin, Gilbert, Arizona

Bob says: "I took this photo of a Spanish mission in Tubac, Arizona, at the Tumacacori National Historical Park. This room was once used as the food storage area."

This week's runner-up: "Dusty Sunset" by Joshua Mozdzier, Kissimmee, Florida

Joshua says: "My son and I were hiking with the Boy Scouts in Lake Wales, Florida, when I was experimenting with some camera settings and snapped this. I thought the dust added a cool effect in front of the the setting sun. I took the photo with a Canon EOS T1i."

To see last month's winners, visit the July Hot Pics slide show. Visit the Hot Pics Flickr gallery to browse past winners.

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This story, "Two Ways to Freeze Action With Your Flash" was originally published by PCWorld.