Photography is primarily about the lighting, and when you can effectively control the light and how exactly the camera records that light, your horizons expand exponentially. Light gives your subject texture, volume, and three-dimensionality – it conveys information.
One of the keys to portrait photography is getting separation between the subject and the background, and if you’re in a studio one of the best ways to do that is to have the subject as far away from the background as possible. This way you can light the background separately (even use a different color light) and use two lights on the subject (when using the 3-light process). This allows for the background to “fall off”, if necessary. Also, with as much distance between the subject and backdrop, you can control the focus of the background better. This is important for creating subtle differences in the shot.
THREE LIGHT METHOD
You’ll want to use at least three (3) lights to achieve the most aesthetically pleasing portrait photos – one key light, one fill light and one background light. For each light you’ll probably want to have two or more shades/cutters, so you better shape and control the light – that’s how you can get those sharp shafts of light. You also might want to consider using a reflector of some sort (could be white foam core, a mirror, crinkled aluminum foil or an actual reflector) to gain more texture, definition and contrast.
The Key Light is the main light for the subject, and it’s important that it’s not too strong (you can always reduce it with scrims or diffusion). Don’t try to have the key light do too much and light up the entire subject like an escaping prisoner. To be most effective the key light needs to be off-axis from the lens by at least 15 degrees, and the Fill Light must be positioned on the opposite side of the camera. The Fill Light plays up the contours of the subject, it will – when set right – provide that perfect amount of detail in the shadow regions (this is what makes photos look extra slick). It’s tricky and time-intensive to get the fill light to add the right amount of light. Also, the fill light is nowhere near as powerful as the key light, as you’re looking to create a fairly decent contrast ratio.
By contrast ratio, we mean the difference between the darkest shadow and the brightest highlight. You can calculate this by using the TTL spot meter to check the f-stop of the highlight (say f/8) and then measure the deepest shadow (say f/1.4); now, while that is 6 stops of light, each stop of light is double the amount of light, so you’re looking at a fair strong contrast ratio, and the heavy contrast ratio is what constitutes the lighting dynamics of any image.
It’s important to light the background in such away that gives your subject enough separation from the background and its texture. This helps add volume to your photograph, and volume/depth is what imbues photos with a 3D feel and enables the subject to effectively leap off the page (or display screen!). Many photographers choose to use textured or colored backdrops to add another dimension to the photograph; this does work as the background light can dance off the surface and provide you with additional definition (and therefore separation).
You want to use shades and screens to help shape, reduce and cut the light from various parts of the subject that you want to de-emphasize. Shades enable you to completely stop the light, thus you can create slashes of highlights. Or even use the shade to be used to reduce the spill from the key light; for example if you set up a black flag (another term for shade) on the opposite of the key light, the black flag will increase the shadow level on the opposite side of the face. This dramatically increases the contrast ratio. By reducing the contrast ratio on two or more elements on the subject, you’ll be able to draw your viewer’s eyes to other more prominent elements of the photograph.
By experimenting and practicing with the lights, shades and screens, you’ll learn how to effectively mold the light to your bidding and that’s when your artistry reaches new heights.