Does “Diffusion” Actually Soften Light?

“Soft light is a thing of beauty in photography – finding it is the real trick.”

-Zach Gray

There is some information in the photography world that says diffusion can make your flash images look better by “softening” the light. Today we are going to explore this and see if it is true or false.

When we first started shooting, the first thing we bought was a Canon 580ex speedlight so we could light our subjects at dark receptions. The issue with that light was if we pointed it directly at our subject, or even moved it off-camera and pointed it at our subject, we would get lots of contrast and “hard” lighting on our subjects. Hard lighting is caused by having a small light source and the result is having “specular highlights” or bright spots right next to dark spots that create lots of contrast.

Light - Hard Light

You can see when you use a small light source like the one used above, that you get a very defined line from highlight to shadow, and the skin can look worse than it really is. There are some hot spots on the right side of the frame and you can see that “specularity” we mention earlier.  This lighting is not right or wrong, but it definitely is not forgiving when not used just right.

Does Diffusion Really Solve this Problem and make light softer? 

hard light

Early on, we got sold on this idea that if you added “diffusion” (or something that evened out the light coming from our flash), we could then get soft light. The myth here is that there is only a partial truth in that. The diffusion itself does not actually create soft light. Diffusion only evens out the light.  It’s the size of the light-source (it getting bigger and bigger) that actually does the softening.

Some diffusers do make your light slightly bigger (takes the light source from 1.5″x3″ and making it 4″ inches in diameter, for example), however, this will not make much difference at all in the softness of light.

Defining Soft Light: 


  (Light from flash image above was softened with a 24×32 soft box at 3 feet away)

Soft light (light that appears to “wrap” around your subject) has a painted-on effect and diffused shadows. Soft light is created when you have a large light source in comparison to your subject. Light is NOT softened when you shoot a small light through diffusion, but rather when the you use a large even light source. Soft light looks great on anyone and we love shooting our clients in this type of light (whether it’s created by a strobe or natural light outside).

The problem with the way lighting modifiers like the Speedlight ones above are sold, is that they tell you that they “diffuse” light, and because you added this diffusion, the light is now “soft.” But the truth is, they only even out the TINY light source you are using, and while that does make the light softer by making it slightly larger (and more even), it does not make the light soft enough for a light-wrapping portrait (or much else). If you shoot mouse photography, then that might be a great way to get soft light on your subject, but for people, you need a light source with a little more size to get truly soft light.

If you want light that wraps around your subject, then you need a light the same size as whatever you are shooting. Once you have that larger light source, if you move that light back from your subject a few feet, the light gets harsher (because it gets smaller in comparison to your subject), and then needs to get even larger!

The Real Solution for Creating Soft Light Portraits: 

The real way to solve the problem of using difficult to work with harsh light that comes out of a bare-bulb speedlight or strobe, is to simply increase the size of that light as much as we practically can. If you take a speedlight (that is about 2×3 inches in terms of the size of the light), and make it 2.5 x 3.5 inches by adding a “diffuser” like the ones shown above, then you will barely even notice the difference in the quality of light coming out. But if you can increase the size (and evenness) of that light by 10, 15 or 20 times, then you can start taking ultra-soft lit portraits that require less guess-work and look stunningly beautiful!

For a real world example, watch the video below from our IN-CAMERA: Natural Light Photography System video workshop to see exactly what we mean.



2 great light modifiers that change harsh light into soft light that we recommend are:

For Speedlights – Westcott Rapid Box 26 inch (this will make your speedlight look AMAZING with even, large light for great portraits! Click HERE to see a live demo of this modifier).

For Strobes – Westcott 24×32 Soft Box (this is one we have used for years and is the one used in the video above, and in MOST of our flash images you have seen over the years. As mentioned, the rule of thumb when lighting a subject with soft light is the light source should technically be the size of the subject being lit. However, as a portrait or even wedding photographer, it can be difficult and very cumbersome to lug around a huge softbox. This softbox here gives us a great balance between beautiful, soft light and ease of use).

Hope that helps! Now go off and take some beautiful soft lit shots of your clients!