Digital Focus: Combat Red Eye

Feature: Combating Red Eye

Red eye: Everyone hates it, yet it's hard to avoid finding a few examples in every batch of pictures you take. That's unfortunate, especially when you find that an otherwise great picture of a long-distance relative looks like Linda Hamilton's character in the movie Children of the Corn. So what is red eye? How do you avoid it? That's what I'll talk about this week.

Understanding Red Eye

You've seen red eye, of course--but do you know what causes it? Red eye is the term for the effect you get when you use your camera's flash to take pictures of people or animals in low-light situations, such as indoors or outdoors after dark. Here's why: In low light, our eyes are fully dilated to make better use of the limited lighting, and the pupils are opened up to a relatively large diameter. When the camera flash goes off, light reflects off the red retina in the back of the eye, and when it arrives back at the camera it lends the pupils and irises an angry red glow.

Eliminate Red Eye With Your Digital Camera

The easiest way to eliminate red eye is to set your camera's flash to red-eye mode. This setting "pre-flashes" the camera flash before taking the actual picture by firing the flash several times quite rapidly right before the actual exposure, forcing your subjects' irises to throttle down and decreasing the size of the pupil a bit. Usually, that reduces the red-eye effect. This red-eye mode isn't perfect, though, and often can't totally eliminate the effect. That's because the human eye can't adjust to a change in lighting instantly, so the red eye control on your camera usually just reduces the effect--it often doesn't eliminate it.

There are other things you can do to minimize red eye as well. You can avoid shooting in a dark room or outdoors after dark, for instance. Red eye never happens in bright light. If you're ambitious, you might also want to look into getting an external flash for your digital camera. Red eye happens because the flash is very close to the lens, so light reflects directly back into the camera. If you can get the flash farther away from the lens--such as by mounting a flash on the camera's flash mount (called the hot shoe), holding it away from the camera on an extension cable, or "bouncing" the flash off the ceiling--you'll avoid red eye entirely.

Image Editors to the Rescue

Those solutions aren't always feasible, though. So what if you end up with red eye in your photos? Many image editors can easily wipe it out in just a few simple steps. To see how it's done, you can follow along while I use Jasc Paint Shop Pro 8 to tweak a photo I took outside one night.

From the menu, choose Adjust, Red-Eye Removal. In the Red-Eye Removal dialog box, you can see two images: the one of the left is the work image where you can apply the effect and the one on the right is a preview of the finished image. Grab the image on the right and drag it around until you can see the eyes. Then use the magnifying glass button on the left to zoom in until one or both eyes fill most of the screen. Be careful not to try dragging the image around by the image on the left, since clicking there will apply the red-eye tool.

Now it's time to apply the red-eye treatment. In the left image, click in the middle of one of the eyes and drag the tool until you've made a circle about the same size as the red portion of the eye. After a moment, you'll see a preview of the new eye on the right image. From there, you can customize the eye by specifying its color, refining its size, and even adding a little glint. If you have a dog or cat with the evil eye, note that Paint Shop Pro even has an animal eye setting. Then repeat the process for the other eye.

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