If there is one essential ingredient for photography, it is light. It really wouldn’t matter how much money you put into your lenses and cameras if they were unable to gather, focus, direct, and record light; your gear would be nothing more than a collection of overpriced paper weights. But image creation doesn’t fall entirely to the camera. The photographer needs to know how to use light. In order to harness the power, dynamism, and idiosyncratic nature of light, it is absolutely necessary for a photographer to establish a real relationship with light. As is true in human relationships, understanding is a key component. Any photographer who wishes to reach their full creative potential should, likewise, make it a point to understand the vital characteristics of light.
When entering into any environment where you intend to make a photograph, the first characteristic of light — whether natural or artificial — to pay attention to is intensity.
The intensity of light may also be referred to as quantity of light. This is just a way of speaking about the amount or strength of light present. As a practical example, think of how your eyes react when you walk into a dimly lit room after spending some time in a brightly lit room; for a moment, you can’t really see much of anything — everything is underexposed. Or, when entering a brightly lit room after being in a dimly lit room, the light is a bit overwhelming — everything is overexposed. A camera reacts to light in very similar fashion; not enough light underexposes, while too much light overexposes.
While you have to wait a few moments for your eyes to adjust to changes in the intensity of light, you can simply change the settings for your camera’s aperture, shutter speed, and ISO level (the exposure triangle) to control intensity. Say you want to do some shooting at the beach. The ideal thing to do would be to wait until about an hour or so before sunset, as the quantity of light is considerably lower than during midday when you run the risk of overexposing parts of your photos. Otherwise, you will have to make some thoughtful adjustments to your camera’s settings in order to get the right exposure. In situations with intense light, you will generally want to keep the ISO low, the shutter speed high, or the aperture small (large f-number). One or more of these adjustments will serve to lessen the intensity of the light recorded by your camera, thus preventing blown out images.
The same principle applies to the opposite scenario; shooting in an environment with less light available will call for you to boost your ISO, slow your shutter speed, or open up your aperture. Each of these adjustments allows in more light and will help you avoid having photos swamped by darkness.
The quality of light is not something we can measure. It is, instead, something we describe based upon visual perception; light is either soft or hard (or some similar descriptive variation).
Soft light is non-directional and typically comes from a diffused source. When you’re using flash and you aim the flash into a white umbrella, for example, you are diffusing the light and softening it. Soft light helps creates smooth, gradual transitions from light to dark without causing strong shadows to appear.
Hard light is harsh, directional, and casts strong shadows and bright highlights. If you’ve ever attempted to take a portrait of someone under the midday sun, you likely noticed your subject’s facial features — particularly the eyes, nose, and neck — cast or were beset by harsh shadows. This is a typical trait of hard light.
Portrait photographers overwhelmingly prefer soft light because it is perceived as more flattering. As alluded to above, photographers use a wide variety of devices known as modifiers in an effort to soften the otherwise harsh light of their strobes and flashes. However, natural light can be diffused also; shooting on a cloudy day or using the sunlight trickling in through a window can create beautiful soft light.
As a general rule, the bigger the light source in relation to your subject, the softer the light will be. Moving that light source closer to the subject, if possible, will also help soften the light.
This is not to say that there are no uses for hard light; hard light, used properly, can infuse a portrait with a striking touch of drama. The quality of light one prefers to use comes down to artistic choice, but the first step in being equipped to make such decisions is having an understanding of the quality of light — soft light or hard light —and its fundamental impact on the photos you create.
3. Color Temperature
Color temperature is all about mood. A photograph may have a color cast or tint of sorts that strikes the viewer as being “cool” or “warm.” This, of course, has nothing to do with the weather at the time the shot was taken. Contrary to what we perceive with our eyes, light isn’t typically crystal clear — it actually has a color to it and that color can vary under certain conditions. A photograph taken in deep shade, for instance, may have somewhat of a blueish hue to it; this is a shot we would refer to as being cool. Conversely, the golden light of sunset would translate into a warm shot.
Color temperatures are measured on the Kelvin scale and range from roughly 1000K on the warm, red end to 10,000K on the cool, blue end of the scale. As a point of reference, daylight and electronic flash fall into the 5000 to 5500°K range; tungsten/incandescent bulbs are rated at about 2500°K to 2800°K.
Color temperature has a profound impact on photography. Depending on what type of lighting you are using on your subject, it has the potential to cause some undesirable color casting in your shots. To work around this and ensure that your photos are accurate representations of the scenes you are shooting, you will have to adjust your camera’s white balance to even things out.
However, this is yet another area where there is a lot of subjectivity. A cool scene can be warmed, a warm scene can be cooled down, a feat made extraordinarily easy with digital photography. Plus, if you shoot raw you can fix color temperature in Lightroom, Photoshop, GIMP, or just about any other image editor. A basic understanding of color temperature and white balance will give you greater creative control over your photography.
In addition to exercising control over the quantity, quality, and color of the lighting being used, a portrait photographer also has some control over the “shape” of their subject’s face. How? By dictating the direction from which the light is coming.
This is rather easy in a studio setting. All you need to do is move your key light (main light) into a position that creates the look you want; the way the light reflects in the subject’s eyes, the way it wraps around the face, the direction and strength of the nose shadow. If a multi-light setup (hair, rim, and fill lights) is being used, the position of those other lights can also be arranged to fine tune everything and further affect the shape of the face.
Being so precise is much trickier when working outdoors with the sun as your main light source. In this case, since the sun can’t be moved, you will have to move your subject around until you get the desired look.
Why does the direction of light matter so much? Because it influences how the portrait is perceived by the viewer. For example, “butterfly” lighting is a lighting technique that creates a symmetrical butterfly-shaped shadow under the subject’s nose and emphasizes prominent cheekbones and good skin. In order to accomplish this glamorous look, it is absolutely necessary to make sure the lighting hits your subject’s face in a very specific way. The direction of light can make or break a shot.
Understanding these four characteristics of light — quantity, quality, color temperature, and direction — won’t magically make you a better photographer. The information is important, sure. But it is useless unless you are prepared to take it from the theoretical to the practical. Light is everything in photography. Learn how light works and learn how to assess it. Once you put those skills to use, you will be well on your way to becoming the photographer you desire to be.