O, feather your light
If you’re aiming for a soft light with your strobes, a bigger modifier isn’t necessarily required. Instead, you might want to try feathering the main light source. Instead of pointing it directly at your subject, you point it slightly in front of (or behind, over or below) your subject. The light from the edges of the light source has a much softer, almost glow-like quality to it.
Direct light on the left, feathered light on the right. Click the images for a larger version.
Not only is feathered light softer, you also won’t have to deal with those hot spots that usually show up in more direct light. As an added bonus you have a better shot at reducing the spill of light on the background. The flip side of that of course is a risk of colour reflections bouncing back at your subject if you aren’t mindful of where you blast the main thrust of your light.
While you can feather with all light modifiers (maybe except a shoot-through umbrella), it’s easier with the straight edges of a soft box or an octa box. There isn’t much point in feathering a beauty dish either, since it’s already constructed in such a way as to produce that glow-like quality then you aim it straight at the subject at a close proximity. The feathering is built in, so to speak.
Diagram for direct light on the left and feathered light on the right. Click images for larger versions.
While feathered light is incredibly soft, you can still give it some directionality. If you’re after a more fashion-like look, with more defined cheek bones, just lift your light source up higher, maybe with the lower edge of the modifier at the level of their chin. I find it helpful to think that it’s the edge of the modifier I’m positioning, not the entire light-emitting surface.
A down side is that feathering requires more strobe output, which is a problem if you use entry level strobes with limited power, like I do. Also, I also find that feathering is harder in a tighter space. You just need a little bit of extra room, in order to move the light more in front of or above the subject. If you can work around that, this is a fantastic tool to have in your bag of tricks.