Diffusion: in regards to photography, this is the softening of light as it pertains to the quality of it. There is hard light which is often much less diffused while soft light is very diffused. Diffusion can break things known as specular highlights–which are little bits of light and details that come out due to the illumination found with light. Flash duration and a number of other things also play a role. But with diffusion, light’s super powers can be nullified.
With Product Photography
Here’s a set that I did for a friend who makes knives. The images without diffusion have harder light and therefore also more details due to the light not being dampened. Of course, there can always be too much light to the point where details are destroyed. But in this case we were able to achieve balance. For these specific knives made of Damascus steel, the details and designs on the knives are very important. These are very fine details that you can otherwise only get with the light hitting at just the right angle. With diffusion, those details are softened. Without diffusion, those details are brought out much more.
Something else that should be noted: silver diffusers can often boost and enhance details. White will kill the details. In the case of shooting portraits, we’ll see that right now.
This shot was done with lighting that was diffused. When the light is diffused, you get a softer look. See how there are almost no shadows on Megan in the image above? This is a result of the white diffuser and, of course, the diffusion. But let’s see what happens with a silver interior diffuser.
The above photo was shot with a light that has a soft silver interior. Soft silver is a combination of both white and silver. Notice how more details pop? However, the details are just enough to not see a ton of pores in the subject. With silver interiors, you’re bound to see pores.
In this image, we see a scene where a silver umbrella was used. Obviously, there is a heck of a lot more pop in the details. Not only is the silver adding those details, but so are other factors like flash duration–which stops fast moving motion. Now let’s look at a portrait with no diffusion.
Here’s the scene with no diffusion on the Phottix Indra. Below is the result.
Quite a bit more detail and pop! However, it can also look good depending on the situation and how you’re feeling. In general though, if you’re going to diffuse or even use diffusion, ensure that the diffuser is larger than the area of the subject in the frame. So if you’re shooting a headshot, make sure that the softbox or umbrella is larger than the head and shoulders to get even and smoother diffusion.