The key to always getting the softest flash output has to do with the laws of physics: let’s explore!
When you know nothing about using a flash, you’re probably going to screw it up. TTL works well, but it probably won’t give you what you want. Here’s a fact of life: machines don’t give us what we want. They give us what we tell them to, and that’s it. If you’re using a flash in TTL mode, but you don’t like the way it looks, you’ll need to adjust it. You can tell it to go brighter or darker. Or, you can switch to manual mode and set it to do something particular. But if you want the most consistency overall, you’re best off following the laws of physics.
How Lighting Works
For us to understand how this works, you need to get a fundamental concept in your head. And that’s this:
- The larger and closer the light source is in relation to your subject, the softer the light source is
- The smaller and further away the light source is in relation to your subject, the harsher the light source is.
Of course, lighting modifiers affect this too. The simplest example is the sun. When the sun beams down on the world during a cloudless day, the shadows are harsh. It’s a small light source, and it’s far away. But when the light from the sun is going through the clouds, the shadows are softer. The clouds are closer to the Earth, and they’re pretty broad in relation. So that’s why the light gets softer. Here’s what that looks like:
Here’s a photo with cloud coverage. Notice how diffused and soft the shadows are under her chin?
See how hard the shadows here? This is a shot when there is no cloud coverage, and so the sun bears down much harder. It’s clearly visible even in her skin.
Using the Zoom Head
When you’re working with a flash, the best way to get softer light is to make the output larger. Luckily, your flash has an easy way of doing that: you can manipulate the flash head. Set it to a wider focal length manually–that’s it. Think about it: if your flash is setting itself to light for a 50mm lens, then the beam is going to be narrower than a 24mm because that lens is smaller. But if you light for a 24mm, then you’re giving more coverage.
So before you even put your flash into an umbrella, softbox, octabank, etc., we recommend setting the zoom head to the widest setting. Some flashes have what’s called a wide-angle diffuser that makes the coverage spread out more. When the coverage is more spread out, then it’s going to go out in a larger area. Larger, once again, means softer light.
The Wide Diffuser or Widest Setting
Because the flash is using a wide diffuser, you also have to get it at just the right distance away from your subject. Usually, that’s a few feet. But if you put it into a light modifier the game changes. You’re going to get a softer light, but it will be softest when the area of a subject that you’re photographing is smaller or tighter than the light modifier. For example, if you’re shooting with a six-foot umbrella, you’ll get the softest light when photographing someone who is less than six feet tall. Specifically, you’ll get even softer light when focusing on smaller details like a headshot.
Try it! You’ll see!