“What is a softbox used for?”, I often hear. “To soften light”, I respond. But it occurs to me that showing you is probably worth a lot more than telling you.
Here’s a picture of a wine glass, taken last night to demonstrate exactly this point:
As you see, I used off-camera flash, so it’s not too bad – but look at the shadows from the glasses’ stems. They are well delineated and sharp and clear. We call that “hard” shadow, caused by “hard” light.
Now let me put a little softbox on the flash:
I used a Honl photo Traveller 8 softbox – one that folds up to basically a flash nothing, and is light and sturdy. A very useful tool, and I always carry one or two.
What does it do? It modifies the light (a “modifier” is anything that changes the direction, size, or colour of the light) by making it bigger. A large light with respect to the subject avoids sharp shadows: the larger the light, the fuzzier (“softer”) the shadows become. Now look at the shadows coming from the glass:
What shadows? They are almost gone now! And that is what a softbox does. Even a small softbox, if close to the subject.
Why “close to the subject”? because what matters is how large the light source is with respoect to the subject, or, if you prefer, “as seen by the subject”. Small gives hard light; large gives soft light. Take the sun: it may be large, but as seen by us, because of its distance from us, it looks small, so it gives hard light. This 8″ softbox, on the other hand, may be only 8 inches across, but because it was close to the subject it looks large. Hence, soft light.
The softbox is better than an umbrella in the sense that it does not throw light all across the room. That is why the softbox is my favourite light softener, and that is why I usually carry a number of them, large and small, when I shoot.
My new e-book “Pro Flash Manual” discusses this and all sorts of other modifiers in detail, of course, as well as teaching you the rest of flash, all in once go. It’s a PDF; just $19.95, contains 123 unprotected (i.e. easy to read and copy) pages, and you can get it here now.