One of the first challenges awaiting portrait photographers new to studio lighting is how to produce soft light. Anyone who has used a flash or strobe knows that there is more to lighting portraits well than simply pointing a light at a subject and rattling off shots. At the same time, creating soft light does not necessarily require an investment in a ton of expensive lighting modifiers. This article covers the basics of soft light along with some light-shaping tricks for achieving soft light with and without modifiers.
What is soft light?
When making a portrait, a light source can be hard or soft. Hard light produces high-contrast images with sharply delineated shadows. Hard light can be used to add drama to low-key images or to emphasize skin texture and imperfections. Soft light is used to produce more neutral portraits with softer, “feathered” shadows. Generally speaking, soft light is more desirable for most portrait scenarios because it can be more flattering to the sitter’s appearance.
How do I make my light soft?
The primary factor determining the softness of a source is the size of the light relative to the subject it is illuminating. Two measurements are important here: the dimensions of your light source and the distance between your light and subject. The closer or larger your source, the softer its light. The farther and smaller your source, the harder its light.
Does diffusion soften light?
No. There is a common and persistent misconception that simply adding diffusion to a light source will soften its effect. Diffusion is extremely useful as a light-shaping tool, but not for this reason. The real benefit of diffusion comes from its ability to scatter light across its surface. This neutralizes hot spots and produces a more uniform effect.
Because the quality and intensity of light changes with each medium it interacts with, the final material a light encounters en route to your subject plays a significant role in how your light will look. However, it is the surface area of that material—not the material itself—that will play a leading role in the softness of your light. If your diffusion material is the same size as your light, it will not soften its effect. Don’t believe me? The strobe used in the triptych hard-light example below, with our model and lighting diagrams, incorporates frosted glass into its head to eliminate hotspots. Its head is only about 5" in diameter. While the light it produces may be uniform, the image shows extreme contrast with hard shadows across the model’s face because it is still a (relatively) small point source.
What about softboxes?
Part of the confusion surrounding diffusion likely comes from the fact that softboxes, which do soften light, incorporate diffusion into their design. However, softboxes are more than just frames that hold diffusion. Many softboxes incorporate internal baffles constructed of diffusion material into their design. This bounces light backward and all around the reflective surfaces inside of the softbox. When the scattered light reaches the front diffusion of the softbox to be evened out, the size (and often shape) of the light source has changed. This increase in surface area is what produces a softer effect.
How else can you soften light?
You don’t need to invest in a softbox to produce soft light. Bouncing a light source from a white or neutral surface can do the trick, in a pinch. Event photographers rely on bounce when working in scenarios in which they cannot use modifiers. When bouncing a light, be careful to avoid surfaces that may add a color cast to your images. The best option for a wide-reaching bounce is a white ceiling or wall. In a studio, you can use V-flats to simulate the effect of a large softbox. Simply fire your strobe into your V-flat and adjust its position according to your desired effect. Be aware that when bouncing your light, you are sacrificing a considerable amount of control in terms of where your light goes. When precision is needed, it is best to use either a softbox or even a reflective umbrella. The nice thing about umbrellas is that they are cheap, portable, and quick to set up. You can even add front diffusion to many models, simulating the effect of a softbox.
Both an umbrella and a V-flat can dramatically soften a light source. This is most visible in the shadows on the model’s face and floor. Also, note how the V-flat affects the image in a broader manner. It even brightens the entire backdrop, whereas the spill of the umbrella, which is more directed, reaches only half of the backdrop.
If the sun Is so big, why is its light so hard?
Good question. It may seem counterintuitive that the sun, which is massive in size relative to any terrestrial subject, can produce such harsh light. However, the sun is also millions of miles away from the Earth. If the sun were closer to Earth, we would all enjoy softer light—as we watch all known life forms melt before our eyes. Luckily, there are safer ways to soften sunlight. Nature provides the cheapest solution: clouds. Remember that the last thing a light source encounters on its way to your subject effectively replaces its original source. Think of an overcast sky as the front diffusion of a massive softbox. The scale of the clouds dwarfs your subject while simultaneously evening out the sun’s light. This produces a neutral effect, excellent for portraits. A large scrim can achieve the same goal when managing sunlight on location. Check out this article for more tips for using scrims as modifiers.
Have tips for achieving soft light? Share them in the Comments section, below!