It can take just a single light to completely change a scene—if you know how to use it. Photo by David Schloss
Whenever I hear a photographer say “I just use natural light,” sometimes what they mean is “because I don’t know how to use lighting equipment.” For most photographers, understanding how to set up and modify lighting to achieve a desired result is a much larger mental hurdle than grasping the connection between aperture, shutter speed and ISO.
Realistically, though, all lighting tools are made to do the same job—increase the amount of light falling on some or all of your subject. The confusing thing about photographic lighting is that there’s just so much of it available, and people often think they have to master dozens of different lighting tools. But if you understand the basics, all of the gear just becomes a tool for taking some light from over here and putting it over there in a specific way.
The other day I took a ride in a private plane with a seasoned pilot, and he went through a long pre-flight and pre-takeoff checklist. As we were flying, he adjusted switches and turned knobs, and to me, it was all a bit bewildering. There didn’t seem to be a correlation between turning dials and not falling out of the sky. If, however, I had a pilot’s license, I’d know what each switch did, even if it were in a plane I was unfamiliar with. I’d recognize the fuel tank switch and the dials for tuning in air traffic control and the flaps adjustment, and so on. I might not know where a switch was, but I’d know the principles of how a plane worked, and once I found the right dial or toggle, I’d know how to use it.
Luckily, lighting an image is vastly easier than flying a plane, although it doesn’t always feel that way. Once you know the basics, the various components make sense.
There are three things that control how light falls on your subject, and to understand how they interact, simply grab a garden hose with an adjustable nozzle. (Note: Let’s just mentally grab a garden hose, things are going to get a bit wet here.) While light doesn’t function exactly like water, it’s close enough to understand basic lighting concepts. Water splashes and sticks around in a way that light does not, but when it comes to intensity and brightness, it’s a good stand-in.
Point your garden hose at a person (if you’re doing this in real life, I suggest someone extremely understanding), stand very close, and adjust the nozzle so that the water comes out in a tight jet of water. You’ll end up with the subject being hit very hard with a stream of water, and that stream only hitting a small portion of their body (ignoring the water splashing onto other areas for now).
Next, adjust the pattern of the water until it’s a wide-open fan of water. The same water now covers more of your subject and is much softer. Back away from your subject with the spray still in a wide pattern, and you’ll end up covering a greater area of the subject, with increasingly softer force, up until the point at which the water no longer reaches them.
At this point, adjust the stream of the water again until it’s a tight jet, and once again, the water should reach your now-drenched subject. The water won’t hit with as much force as when you sprayed it close, and it will hit a wider area, but it will still cover a smaller area than the misting setting and feel much harder to your subject than the mist—but significantly less so than if you were standing close.
At this point, if you want to get more water to reach your subject, you can either move closer or increase the water pressure so that more water is coming out of the hose per second. Either way, you’ll have more water hitting your subject, but you’ll have a different quality of water.
The larger the radius of the water is, the softer it is when it reaches your subject, and the smaller the radius of water is, the harder it is when it reaches your subject. That’s because as you open up the spray of water, more of the water molecules strike the subject from a variety of angles, while a tight spray of water sends most of the water in the same direction.
The closer you are to the subject, the more forceful (intense) the water is when it hits your subject, and the farther away you are, the less forceful it is when it reaches your subject. That’s because as you move away from your subject, the water molecules spread out over distance, so they’re hitting a wider surface area.
Replace the water in this analogy with light, and the same thing happens. Wide, far-away light is the softest, while narrow, close light is the hardest. The wider your light source and the farther away it is, the softer your light, with less light arriving at your subject the farther away you get.
The entire trick of lighting is to take your light source and find the right distance, brightness and shape to create the lighting you want. This can be done through the right selection and use of lights and modifiers.
All you really need to remember is that the farther and the larger the light source is, the softer the light on the subject.
But wait, I can hear you think: When you take photos outside with the noonday sun shining on a subject, the light is really harsh—and what light source can we find that’s bigger than the sun? The issue here is that we’re only getting a small section of the sun’s light—most of it has gone off in other directions before it hits earth. The result is an effectively small light source that’s far away. If you look at it (don’t look at it for real, that was a mental experiment), it appears to be a small point of light smaller than even a typical flashlight.
That’s why cloudy days are so great for photography—clouds cover more of the earth than you or I do, so more light hits them, and the clouds diffuse and diffract the light, and the result is a soft light covering the earth.
The Inverse Square Dance
One of the crucial ways in which streams of water and beams of light differ is in the way they travel to their destination, and what happens along the way. Beads of water are pulled to the ground by gravity, but that doesn’t affect light (well, it does, but let’s stay clear of advanced physics for a now). Spray water here on earth, and it’ll eventually be pulled to the ground by gravity and friction with the air.
Shoot a beam of light, and it will travel indefinitely until it’s absorbed or hits an object that converts it to heat. Stand under an intense light source, and the heat you feel is your skin absorbing some of that light and converting the photons into heat.
The way that light travels across distance is governed by something called the Inverse Square Law, which is a complex-sounding way of saying that as you double the distance from a light source, only a quarter of the energy reaches the subject. In other words, if your lights are a distance from your subject, let’s say 1 yard, moving the lights to 2 yards away doesn’t mean you’ll get half as much light but a half of a half as much.
If you’re good with ƒ-stops, you can think of this in terms of stops of light instead. Imagine that, with a strobe positioned 1 yard away from your subject, you set up lighting so that your photo is properly exposed when you set your camera at 1/60th at ƒ/22 at ISO 100. If you move your lights to be 2 yards away from the subject (double the original distance), you’d now be losing two stops of light, and to get the same exposure, you’d need to set the camera to 1/60th at ƒ/11 at ISO 100. Move the subject back to 4 yards away (doubling the distance again), you’d lose two more stops and now have to set the camera to 1/60th at ƒ/5.6 at ISO 100.
If you’re not good with ƒ-stops, just remember that as your light gets farther away, you need to either increase the intensity a lot or change the camera’s settings a lot to keep the same amount of light.
What are the implications of all of this on your choice of strobes? With an understanding of how light works (or garden hoses, depending on how much you understood my analogy) you can figure out what kind of lights and what kind of modifiers will work for you.
Small, Harsh, And Crucial—Portable Flash
In our garden hose analogy, it’s clear that portable flashes, the kind that sit atop your camera and/or that can be used wirelessly off-camera, are the equivalent of spraying a close, narrow blast of water. Without any modifications, they’ll produce a harsh light on a close subject, and, thanks to Inverse Square, throw little to no light on a far-away subject.
Sometimes you want a narrow, intense light, either because it’s what the photo calls for or because it’s all you have available. If you move the portable light away, you don’t end up with entirely smooth light because you’re still dealing with a small lights source.
One solution is to put a diffuser of some kind, like a softbox, in front of the light. You’ll lose a lot of the power of the light, but because of the way the material is constructed, you’ll make a bigger light source with your small strobes. There are countless models of softboxes for flash units and adapters that let you put one (or more) flash units together inside a studio-sized modifier.
You can also bounce the light of the strobes off walls and other surfaces, essentially turning the walls or ceiling into a diffusing material.
Big, Heavy and Beautiful—Strobes
On the opposite end of the lighting spectrum (I couldn’t resist), we find “studio” strobes. With bigger lighting elements than flashes, these produce a softer light at the same distance, and with greater power, these can be moved back much farther and still have enough light to reach the subjects. They’re also powerful enough to light a subject even with light modifiers like umbrellas and softboxes mounted to them.
Strobes can be AC powered for unlimited flashes, or they can be battery powered, which limits the number of “pops” (flashes) they produce but makes them portable. If the strobe has a separate component that plugs into an AC outlet, that is called a “pack,” and the individual lighting elements that connect to the pack are called a “head.” Most packs have to be plugged into outlets to function, though an increasing number of packs can run on battery power or AC power.
Some strobes have the pack portion built into the light, for portability, and these are called monolights. Both standard pack-and-head kits and monolights can be battery powered as well.
The power of a strobe system is listed in watt/seconds—a fancy way of saying how much light it produces in a certain period of time. A 300-500 w/s pack is on the low end of the power scale, and a 1200 w/s or higher is on the upper end. How much power you need depends on how far away you plan to shoot and the type of modifier you’re planning to use. All the units can be scaled down, so a 1200 w/s unit can still flash at 200 w/s, but a 500 w/s unit can’t produce more output than 500 w/s. That means that when purchasing lighting gear, it’s better to buy a bit more power than you think you need.
Many strobe “packs” can power more than one strobe head, which divides the total power across them. Plug in two lights to a 1200 w/s pack, and you’ll usually be able to decide individually how much light each head produces to a total of 1200 w/s, though some systems just divide the total power across each head.
An increasingly popular choice in photographic lighting is continuous light sources, like LED panels. Before LEDs became cheap and ubiquitous, the main type of continuous lighting was HMI lights, which were expensive, heavy and hot.
LEDs are lighter, cheaper and cooler, and getting more powerful by the day. Turn on an LED light and you can see exactly where the light is going to fall. Put something in front of the LEDs to soften them, and you can see the effect of the use of the material. It’s a straightforward way to work. In order to get the same level of brightness as a flash can produce, you’ll need very bright LEDs, and since they’re always on (by definition), these can be harsh on the eyes of your subjects. Sometimes there’s no substitute for flash.
All Shapes And Sizes
There are a ton of different shapes for light modifiers, and they come in a wide range of sizes. The most common of them are designed to enlarge the light source (to make it softer) and to shape it a bit.
A popular modifier (especially for beginners) is an umbrella. These slide into the light body or the stand and point toward the subject, with the light pointing backward toward the umbrella. It’s the fastest, easiest light modifier to use.
A light-modifying softbox can be square, rectangle, octagon (usually called an “octobox”) or circular. A commonly used circular modifier that’s shaped like a fancy lampshade is called a “beauty dish” for the excellent portrait light it creates.
The surfaces of the modifiers can often be changed, with different colors for different needs. They’ll often come with inserts that are white, silver and gold—gold is a good one for flattering, warm skin tones and to match tungsten light.
There are also light modifiers designed to limit how much light comes out, in order to direct or shape it. Some common modifiers like this are snoots (long tubes that make the output look much more directional) and barn doors, which can be moved in front of a light to cut off the edge of that light.
Part of the reason that flash photography is so bewildering to many people is that there are just so darned many accessories available. There are dozens of companies making light stands; there are hundreds of different clamps on the market. Many of the studio strobes have their own system to connect the lights to modifiers, so there are adapters available to take a softbox from Company A and put it on a light from Company B. There are portable reflectors; there are pop-open boxes to put models inside for soft light photography.
All accessories, though, perform a task, and as you work with lighting more, you’ll come to understand what they are and what they do. Photograph a model wearing a cowboy hat, which casts shade onto the face of your subject, and you might think “if only there was a tool to bounce some of the light under the brim of the hat.” There is. It’s called a reflector, and they come in different sizes and materials. There’s even a modifier designed to reduce light, a black sheet or cloth called a “flag” that helps reduce highlights and cut off light sources.
If you think it would be great to hang lights from a pole above your subject, you can. Almost every possible photographic scenario has been considered, and an accessory (or a thousand) exists to solve any problem.
If you want to learn more about what the accessories do, simply browse their descriptions in an online store. Often, you’ll find exact details of what the accessory does and videos about how to use it.
A Flash Of Clarity
One of the most confusing things about working with photographic flash lighting is that you can’t see the effect of a setup until you review the images. This is disconcerting to photographers, as we’re used to seeing our composition as we’re creating it. Setting up strobes is largely a matter of trial and error and experience. Just as a seasoned photographer can evaluate the lighting in a scene and dial in the aperture and shutter speed, a photographer who’s used to working with strobes can look at a scene and get a feeling for how much light they need.
Even if you plan to work with continuous lighting, it’s important to master flash and strobe photography, because there are going to be times when the subject requires it. For the photographer new to strobes, simply set up the lighting gear, get a willing subject and play around. There’s no better way to see how lighting gear works than by trying it out. If you take a shot and it’s overexposed, turn down the power or change your f/stop or shutter speed; if it’s overexposed, increase the power or change your camera settings. It really is that easy to become proficient in lighting.