In this article, we are going to attempt to mimic the traditional 3-light (key, fill, and hair light) setup for portraits with just a single light source. By “one light”, I don’t mean a single light positioned at the usual 45-degree or 90-degree to the subject kind of light.
Much can be done with one solitary light source, especially when the flash is not mounted on the camera itself.
Admittedly, I’m not very well versed (yet) beyond the fundamentals when it comes to off-camera lighting with a small flashgun as it’s simpler to work with studio strobes or bouncing a flash that’s mounted on the camera, for me, at least.
I recently bought myself a set of Flashwave 2 radio triggers for my flashgun (review coming within the month of May) and it really opened a whole world of possibilities with lighting even with a single flashgun.
Using a single light from a studio strobe is a very common technique, especially when establishing contrast is important (especially with monochrome images).
I’m curious as to how far we can go to produce a decent image with a single light, focusing more on creating an illusion of having more than one light to add depth to our images.
As mentioned earlier, the size and flexibility of strobes make them easy to use, and compared to small flashguns, strobes are less fiddly and easier to control the light quality.
Having said that, a regular hotshoe flash is much more portable and you can fit 3-5 flashguns in a normal sized camera bag, which make them extremely versatile to use when you’re in a tight budget or if you need to light on-the-go.
Search for the keywords: “One Light Portrait” in Flickr or Google and you’ll find some really great creative light positioning that resulted to stunning photos with just one light source mimicking multiple lights. My favorite, by far, is this one.
The whole concept of this exercise is just applying the law of reflectance, as mentioned in my older article, Controlling the Direction of Light.
It’s just a matter of playing “connect the lines”, so to speak. Know where the light is coming from, reflect the light to another surface, and redirect the light again, as necessary. Angle of incident = Angle of Reflectance as light travels along a straight path.
Law of Reflectance
Let’s get started. All images were shot at 1/200 @ f/5 ISO 250 – 40mm or so. Flash set at 1/36 power, 80mm zoom. The last (final) image was shot with 1/80 to let more ambient in, the rest of the settings are the same.
Image one: Main light only
Yes, our main light is a hair light. The hair light skims across the subject’s head, missing the head for the most part but rendering just enough rim light around the head. Most of the light passes through unblocked to the subject’s left ear.
The flash was set to 80mm zoom, but it wasn’t tight enough and the subject was moving back and forth (he was busy playing his PC game) hence a little too much light spilled to his cheeks. A snoot or grid would’ve helped tame the light beam.
You notice also that the subject’s left cheek already has some light on it, that’s because he was just 2ft away our white wall to his left. You can see where we’re going at now, right?
Image 2: Add silver reflector for key light.
I held a silver reflector to the subject’s left, slightly above his head, angling downwards. You can see the slight Rembrandt lighting forming the triangle highlight under the subject’s right eye at this point. If he wasn’t looking downwards, we’ll see a catchlight around his pupils.
We now have two light sources!
Image 3: Adding a fill light.
As you can see, there’s too much contrast in Image 2. The bright left side versus the dark right side created a high-contrast image, not quite ideal to what I’m after. We can now add a fill light to the shadow side to help “lift” the shadows a bit, reducing contrast created by our key light from the reflector.
I added a small 8″ standing mirror very close to my son’s right cheek. Again, the new reflector has to catch the light that the silver reflector is producing, otherwise, it won’t work.
I used a mirror for two reasons. First is because it’s more reflective than a white or silver reflector. The reflected light coming from the silver reflector is already quite weak and soft by the time it reaches the subject’s right side, so using a silver or white reflector will not suffice. Adding a mirror will reflect more light back as a mirror is more efficient in throwing light back. Second is because I don’t have another reflector available at that moment and I was too lazy taking out my foam board for this tutorial.
To be honest, it can be improved further if my mirror was larger. I only realized I have a 4ft mirror in the closet after writing this article.
The photos above took less than 10-minutes from measuring the first shot to the final output. I got lazy and just placed the flash on the sofa cushion and hand-holding the reflector. The results could be a lot better with a properly sized reflector and light stands, but you get the drift. Here’s the lighting diagram.
Lastly, you’re not limited to replicating three lights. Check out the video below from ProPhotoLife.com (Jim’s site is one of my absolute favorite sites around, his videos are just awesome) for other ways to manipulate a single light source.
So there you go, one flash achieving key, fill, and rim light. With more finesse (than I presented), you can have simple and fundamentally sound lighting in your portraits.