Soft light comes from a diffuse source. The classic example is an overcast day, where the light comes from everywhere and there are few, if any shadows. Other examples of soft light include studio softboxes, diffusers, and reflected light from a large surface (e.g., a ceiling). All of these need to be near the subject, otherwise they begin to act more like hard light…move an umbrella reflector away from the subject and the light becomes harder.
Shadows on an object lit with soft light have a less-defined edge, and they are not as dark. Because it does not highlight blemishes, scars, and wrinkles, soft light tends to be more flattering for people. For this reason, portraits normally use soft light, as do some glamor shots.
Here is one of my favorite soft-light shots illustrating this type of lighting.
This is the second in a series of blog entries about hard and soft lighting. The previous entry is Hard Light.
I am not the first to write about the distinction between hard and soft light. However, I recently prepared (and gave) a talk for the 2011 National Speleological Society (NSS) convention, and I learned a bit in doing the preparation for the talk. The results for this will be spread across a few blog entries to keep each one tight and on a specific topic. As I finish them, I will link them all together.
First, definitions. Hard light is light that has sharp edges to the shadows. It comes from a small light source or a large one far from the subject. Most speedlite/speedlight flash units are relatively small light sources. The sun is large, but it is far away, so it also is a hard light source, especially near noon.
Hard light is good for showing textures and fine details. This is great for photos like geological features, but few people want every last blemish and wrinkle highlighted in the photo unless it is to show character as in this example.
Young people, such as this lovely young woman, can also take hard light because they have great skin.
Shadows in hard light tend to be dark with few details. The high contrast can create a moody image that can be dramatic. Film noir movies are classic examples of this type of lighting.
You can also soften hard light by using a second (and possibly more) light source. If you have no modification devices that soften the light, this approach alone might be sufficient. Position the extra light(s) so they fill the deep shadows. I normally set the second light to be about a stop darker than the primary light, but the exact ratio depends on the situation.
To summarize this blog entry, hard light comes from a small light source and produces high-contrast images with dark, well-defined shadows. Sometimes, it is exactly what you need to set the mood of an image.