Sometimes you want to add a bit of light to a small, well defined area of your image. Maybe you want to splash some warm light on a subject’s face, or create a rim light that only outlines your subject’s jawline and not their hair/shoulder. Light control of this kind can be difficult to achieve. Grid spots can work, but the falloff can be undesirable. With bigger studio lights barn doors are often used to flag off parts of the image from getting too much light, however on speedlights (which usually don’t have modeling lamps) it can be hard to tell where the light is going to go and where the shadow areas will begin.
I had these old barn door attachments for small studio lights, and I wanted to set up a speedlight rig with them. so I taped one to the front of a speedlight, and then wedged a “visor lamp” into the top. With that arrangement I had a small modeling light to see where the light was headed, and barn doors on the speedlight to restrict the light from going everywhere.
It’s not a perfect setup. The “visor lamp” is a bit off center, so the light from the speedlight goes just slightly above where the lamp indicates it will. But it works pretty well at giving you a sense of where the light will go. It’s a great arrangement for throwing some hard light on a subject, or splashing light exactly where you want. I’m looking to get a subject in front of it soon, I’ll be sure to post the results here when I do.