Sometimes you run into a situation where you a) have very little space, and b) need very soft and even light. If you happen to have two lights, you can make your life very simple. Again this wonderful tidbit originated (for me anyway) with the Strobist blog, but I’ll share it again just in case you’re scared to dive into things there.
The short and skinny is simple. Get two light stands, and two shoot through umbrellas. Raise one of the umbrellas up high and angle it down towards your subjects. Make the bottom of that umbrellas a few inches above where the top of your lens will be. Take your bottom umbrella and put it under the top umbrella, leaving maybe a foot or two of free space, and angle it up some. To do this you’ll need to have the legs on one stand flat and wide, and the other raised up and narrow. Weighing down the top stand is wise if there’s going to be any potential for wind, or people moving about the area. Set your exposure as you normally would, leaving both lights at the same power will give you what almost looks like a giant light bank. You can mess with lighting ratios a bit for a more three dimensional effect, I usually just shoot both strobes at the same power.
The setup looks something like this:
Stack your umbrellas
The result looks a little like this:
Clamshell Lighting Result