A fundamental lesson in photography is the exposure triangle. Learning about ISO, shutter speed, and aperture is something all photographers should do.
What Are Zones?
In this article, I will not be teaching the exposure triangle. Instead, I’d like to consider that because these choices are made, either by a photographer or a complex computing program within a digital camera, that a photograph is a sort of copy of the real world.
Sight occurs when light bounces off a real-world object and enters our eyes. Eventually, our brains process this visual information regarding light and compute it to offer an image in our mind, which has a lot of dynamic range. We can see light, dark, and light and dark areas together within a single image.
When these decisions are made for the taking of a photograph, however, they are not quite dynamic, but static. That is to say, the three things (ISO, shutter speed, aperture) are decided, and then, an image is taken. And once it’s taken, there is mostly not wiggle room to change the image. So, if you overexpose or underexpose a part of the image, that information is mostly lost.
As an example, imagine it’s a bright sunny day outside and you are in your room with the lights dimmed. If you look out your window, you can likely clearly see what is outside as well as still being able to distinguish what is in your room. Instead, if you were to take a photograph of this scene, you’d be able to expose for the outside or the inside and lose details on the inside or outside, respectively.
It's not so much that a thing is dark or light, but rather that you can expose parts of an image to be darker or lighter than it may actually be. This concept of zoning an image was detailed by Ansel Adams. Through exposure (and darkroom techniques,) Adams showed that an image with greater dynamic range could be photographed.
Three-point lighting is pretty much what it sounds like. It’s a technique that was used fairly heavily in the mid-1900s for portraits; the brightest light is positioned behind and onto the hair of a subject, another is from the front but less bright, with a third from the front but other side, which is even less bright. The overall effect creates dimension and separates the subject from the background.
As an exercise, consider the image of the cube above, which was lit with three-point lighting. You’ll have to take my word for it, but the actual cube was the same shade on all sides. However, through lighting and the zone system, the image of the cube has a certain three-dimensionality.
If you are starting out with studio lighting, this is a great exercise to try with two lights and a reflector. You can also try it with other objects or even a person.
As outlined above, start with a single light from behind the subject and set the exposure so that this is the brightest part of the image.
Next, set a light from the from about 45 degrees to the left and slightly darker.
Finally, set a reflector about 45 degrees to the right to fill in the other side of the subject with light.
As a caveat, outside of this exercise, I’ve only used three-point lighting maybe once in the 10-plus years I’ve been a photographer. So, why would I turn around and tell you to try it?
Well, it’s not so much about learning how to do three-point lighting. Instead, the intent is to show that not only can you sort of manipulate lighting to create parts of an image which are lighter or darker.