A common side effect of introducing flash on your subjects is that of “red eye” – those garish red dots that appear in peoples eyes (or green eyes in pets). We all know it’s from the flash, but sometimes you need flash in a shot to provide enough light for exposure to work. So, what can you do? Well, most of us can probably agree that the best approach is to move your flash off-camera. While this is true enough, the reason why this works isn’t because the flash is off the camera, but more accurately, because the camera is off-axis!
Here’s what happens – when you line up your camera to your subject, an imaginary line can be drawn from the front of your lens to the face of the subject. When you “pop” that on-camera flash up, it is pointing directly in that path, and while the goal of lighting the area is achieved, it’s happening right in your models face. Here’s the classic setup you’ll see a lot of people using that produces red eye in their photos:
So, that’s why most professionals try to avoid on-camera flash for portrait work. Most often, we use wireless triggers to fire flashes that are positioned off-camera, either to the left, the right, behind the subject (called hair lights), or any combination of the above:
Any of the above scenarios could avoid the occurence of red eye in your photos. There are other accessory lighting kit items as well, including soft boxes, shoot throughs (which I’ve talked about before), reflectors, and umbrellas, but sometimes you just have to use that on-camera flash, so what to do then?
The answer lies in shooting at an angle. Remember that term “off axis” I used above? You need to get that axis off your subjects face. Get yourself above or below the straight on shot. You can also turn them to the left or right a tad (and I would recommend this just from a portraitist perspective as it makes for better posture.) Other tactics include some neat light modifier tricks, including gels, diffusers, and the like. I know folks that put a very subtle gel on it, others who have cut out pieces from a milk carton to use as a diffuser. Heck, even a sheet of paper or a napkin (if you’re in a bar) could work in a pinch. The ultimate goal is to avoid that harsh garish light bouncing right off your subjects face, with the resulting red eye!
There’s a multitude of ways, and I certainly have not cornered the market on ways to diffuse light or avoid red eye, so if you’ve got your own ideas, tricks, or unique ways to deal with this issue, sound off in the comments!