Substituting an Umbrella for a Ring Light
Save some bucks, and/or get a completely different look, inside.
I usually use some kind of fill light on, or near, the optical axis. The classic solution is a ring flash, but an umbrella right behind the camera can be a good substitute.
A ring flash will give you a signature wrap-around shadow on any background near your subject. This can be true even if your ring is only being used as a fill. It is just the nature of the beast. Sometimes that works for you, but sometimes you want to get rid of it.
One way to nuke that shadow is to throw a little light on the background just to overcome the shadow being created by the ring. Such was the case in this portrait (left) of Ian in Leeds last spring. You can overpower it, as here, or you can just give it enough oomph to fill the shadow without leaving a glow of its own.
Another way to get away from the ring shadow is to use an umbrella behind the lens. Generally, you are going to have a little more light up top only because you will be blocking some of the light that coming from the lower half of the the umbrella.
Consider the photo of Lem, at the top of the page. This was an instance where an on-axis umbrella was not only cheaper, but absolutely better than a ring would have been. Any shadow on the wall being created by the umbrella is happening below Lem, and is blocked by the chair.
The background light is a bare speedlight being skimmed across the wall at a hard angle from back camera left. The key is just a gridded, 1/4 CTO'd speedlight coming in from back camera right, just raking his face. Everything else is being lit by the umbrella behind the camera. It's such a big light source -- and so close to the axis -- that it does not call attention to itself.
If you want to create soft, on-axis fill much like the light on Dasha (left) you can do that with an umbrella, too. Although this photo was made with an ABR-800 and a Moon Unit, you can approximate this single-light look with an umbrella right behind your lens.
You'll just need to do two things -- make sure the shaft of the umbrella is right on the lens axis, and get your light-blocking butt out of the way.
Easy answer: Use a tripod. A camera on sticks with even a small umbrella exactly behind the lens will get you some pretty cool light. And a big umbrella will really make something special. You may want to cover your eyepiece (shutter on a Nikon, cap or gaffer's tape on other cameras) to keep that light from influencing your chip from the back.
Experiment with the exposure, too, as putting someone on white seamless with this light and giving a little extra exposure can give you a very etherial look. Especially cool, when you consider you can do it with one, cheap light.