“Treat your friends as you do your best pictures, and place them in their best light.” — Jennie Jerome Churchill
Unlike taking a photo, where you try to adequately capture what a scene gave you, there is more control when you make a photo. With a few exception, you tend to have a lot of control over many aspects of the shot, including subject, background, and today’s topic: lighting.
There are really only a handful of ways to modify light, even though the number of tools with which to do so are infinite. Don’t get lost deciphering between strobes and hot lights and soft boxes and umbrellas and diffusers and reflectors and lions and tigers and bears. Oh my. As I always say, if it’s hard, that means you’re doing it wrong.
Size does matter
The first thing one should know about controlling light is that a large light source creates soft shadows, while a small light source creates hard shadows. One example of this might be the difference between the harsh, high-contrast light you get on a bright sunny day versus the soft, beautiful light you get on a cloudy day. The sun by itself is (figuratively) a small light source — just a dot in the sky, really. By comparison, on a cloudy day, the sun lights the clouds, but the clouds are your light source. The world’s biggest softbox, for free!
Along with that, you should remember that distance changes the effective size. A light with a 30-inch umbrella may be many times the size of a person’s head, but it won’t create soft shadows if it’s 10 feet away. Similarly, an 18-inch reflector really isn’t going to be much good in the hands of an assistant, because it’s small size requires that it be very close to your subject — that is, your model needs to hold it.
What set’s you apart
The second important thing to remember is that light — or, more accurately, changes in light — are what tell us what we’re seeing. We need the modeling of shadows to convey a three-dimensional shape in a two-dimensional image. I know that’s a vague statement, but if you keep it in mind you’ll never have any problem figuring out where to put your light source(s).
The need for modeling of shadows is the reason why good photographers never use their camera’s built-in flash as a main light source. (Some do use it, as fill.) Since shadows show in the places where there is no light, a flash coming from the same direction as the camera is going to leave the shadows where they do no good!
Why do professional portrait photographers put a light on the background? It creates separation. That is to say that it reveals where the subject stops and the background starts. This is also why glamour photographers have an extra light set up just to light their subject’s hair.
In the first photo above, there is a large, soft light source from camera left creating nice shadows, but without any fill, background, or rim lighting, the light just falls off into obscurity. You can’t see where the subject (me!) ends and the background begins. Sometimes this is the desired effect, but sometimes it is not. In the second photo, lights from behind on both sides separate the subject from the background, and reveal details in the hair, pose, etc.
It’s all black and white
And the final thing to remember is that where photography is concerned, light goes from black to white. Period. Too much light (for the exposure) will result in an all-white photo, no matter what color the light is. And too little light will always result in black. Not only does this mean that proper exposure is critical for getting your colors right, but it also means that with a little creativity in your exposure you can intentionally get your colors wrong!
If you intentionally overexpose the sky, it will turn white, allowing you to make some interesting fine art photos of leaves or flowers, even without a studio. Likewise, with an off-camera flashgun, you can underexpose on a sunny day and still get a black background. Try it!
One of my favorite examples of this was a photo shoot I did in a location that had no great backgrounds. I was able to muster up a red bedsheet, but I really didn’t like the look I was getting from that. The solution was to crank up the lights and completely overexpose the red material until it turned white. As you can see, the results were pretty cool.
In the first two photos, the background is not truly black, but by under-lighting and under-exposing the background, I was able to obtain the black color I wanted for the photo. In this third photo, the background was nowhere close to white, but by flooding it with enough light, I was able to turn it white (and get a little bit of magenta spill onto the subject).
That’s all you really need to know about controlling your light. Yes, there are more things that are good to know, and maybe I’ll touch on them in the future, but if you remember these three things there’s no reason you can’t figure out the rest on your own.