Reducing Red Eye – Without Annoying Flashes
Red eye – the demon eye effect – is the bane of candid portraits everywhere. You see it in party photos, off-the-cuff candids and unplanned portrait attempts. You'll notice that red eye is not present on professional studio portraits. Why? Because they're using proper lighting equipment: soft boxes, umbrella reflectors, and a bunch of other equipment you may not have heard of. I won't get into all that, because that's not for common folk. But I will tell you how to eliminate it in ways that won't hurt your wallet or your arms (some of that stuff is heavy).
What Causes Red Eye?
Before I go on, it's only fair to discuss what causes red eye. In short, it is the light that is reflected off of the retina – the curved surface at the back of your eye. The retina is filled with blood vessels, thus the cause of the red color. The effect is most common when you are photographing someone with a flash that is mounted very close to the lens. This is especially going to be noticeable with pocket cameras, but is also common with consumer level SLRs with on-camera flashes. Red eye is also common when shooting portraits in low light – the eye's iris opens wide to allow a person to see more light, and there is a much larger area for the light to enter the eye, and in turn exit the eye on rebound. This can all get very technical, but the technicalities aren't going to make it any easier to understand, nor will it help you correct the problem. The important thing to note is that if you have a camera-mounted flash, you have the potential for red eye in your portraits.
Correcting the Problem
If you must use a flash, there are two essential ways to control red eye: Reduce the pupil or control the light. I will discuss each separately as each has its own set of benefits and problems.
Reducing the pupil is easier than it sounds. All you have to do is increase the amount of light long enough before the shutter snaps open so that iris will naturally contract yielding smaller pupils. You can do this by increasing the amount of ambient light – no on-camera flash portraits in dark rooms. The additional light will not only decrease the pupil size, but it should provide additional light for your exposure. If you cannot increase the ambient light, you could trick the eye. You can trick the eye by shining a flashlight in the subjects eye a few seconds before snapping the photo, or even by using your red-eye reduction flash. The latter simply pulses a flash one or more times before actually taking the shot so that the subject's pupils contract. The idea is that by the time the eye reflexively tries to adjust, you will have already snapped the picture. There are four very important caveats about red-eye reduction flashes. First, people have a tendency to blink when the first flash is fired. Especially with groups, you'll be hard pressed to find a shot without some closed eyes. Second, sequence of flashes will slow your shooting rate. This may or may not be a problem, depending upon conditions, your preference and the environment. Third, people may not expect the extra flashes and may begin to move out of their pose after the first flash. As always, you should communicate such aspects with your subject. And finally, the psychological consideration: Small pupils are perceived as unwelcoming, so this may not be desirable depending on your intent. If you want a welcoming shot, you'll want wide-open pupils.
Light control is the best and most desirable method of avoiding red eye. The name of the game is big angles – the angle created between the lens, the eye and the light source. The wider this angle, the less likely you will see the red eye effect. hot-shoe flashes are a start. This adds some distance between your lens and the flash, but it's not always enough. If you bounce the light source off the ceiling or a nearby wall, you've maximized the angle and red eye is not going to happen. You can un-mount the hot-shoe flash and trigger it remotely – either with a remote cord or a triggering mechanism (there are many ways to trigger a camera flash that I won't get into here). Alternatively, you can use a diffuser on the flash. A diffuser splits the light source into several angles – a cloud, if you will. There will be direct light into the eyes, but not enough to cause problems. But this is somewhat of a side-effect as the real reason to use a diffuser is for light quality.
If you don't have an off-camera flash, don't worry. There are plenty of ways to compensate. You can carry a pocket mirror to bounce the light. In fact, we reviewed a product designed specifically to do just that. There are also products available to diffuse your on-camera flash. But you don't have to spend much money. I find that wax paper, index cards or parchment work nearly as well.