After we assemble our umbrella kit, then we place them in front of the subject. The topic then becomes Lighting. This article is more about the philosophy of learning, than about the techniques.
At first, photography novices simply don't know what to look for, and we overlook so much in our flash pictures. At first, we naturally may think we do look, but we do not see yet. At first, we don't know what we are looking at, or looking for. We only see what we want to see, which is not the same as searching out all details. Everyone has been there, at first. Lighting is not the same as exposure or brightness, there is a lot more. To see the lighting, to actually recognize its elements, we have to learn to stop and look at the actual shadows and tonal gradients we create. Seeing is about awareness. This becomes easy automatic habit, but it isn't easy at first, we don't even know we don't know, not until we become aware.
This awareness takes a conscious decision to stop, and actually look, and think, in a determined way, to search your images at length - to realize what we see. I wish I were better at it, but I have finally learned there is much more to be seen than beginners ever have a clue about. We can spend many years still as a beginner (been there, done that), until one day, we realize we have to look, and see. To have a clue, we just need to practice looking, learning to actually see. And then our life changes, at least with regard to photography and lighting. Study your photo results carefully, numerous times on multiple occasions. The more you look, the more you can see (if you try), and thinking about what you see becomes the norm. Then, after awhile, you easily see more, automatically. Think about what you see, search out every shadow, every gradient tone. What do you see? (think about it). Was there a plan for the lighting? Account for each light, and account for their shadows, and their location and degree. The lighting is about the shadows.
By "shadows", I do not mean the shadows behind the subject. Generally we try to eliminate those (with close umbrellas, and more distant background, or bounce). I mean to look at the shadows and shading on the subject, on the face, shadows creating natural gradient tonal shading which adds interest, which sculpts (shapes or models) our subject's curves. This is what we try to create with the off-camera lighting. We know where the light was, and see what it actually did, and learn what the shadows actually show. And then we can better plan those shadows and gradient tones (not necessarily specifically, but certainly generally - a natural look that we might call "avoiding the flat deer-in-the-headlights look"). This is hard to describe, but here is an example from the bounce page. It's just a snapshot, one bounced speedlight on camera, but the point is that the lighting is not flat.
Note that these shadows (gradient tonal variations) is why studio light modeling lights are called modeling lights. From the big dictionary: "Modeling: The technique of rendering the illusion of volume on a two dimensional surface by shading". "Model" in the sense of to help visualize something. The modeling lights show the sculpting or shaping that the setup of our flashes will create with shadows. These incandescent modeling lights provide a continuous light so we can see the shading that the instantaneous flash will create. Which is good, but now that we use digital, our first setup test shots can show the same results, but certainly the modeling lights were essential in the film days. Note though, the idea is about looking, and seeing. We have to look, and we must learn to see.
It is true when showing people your pictures, they don't see this detail either. They do see it is a pleasant natural attractive picture that they like, but they don't realize why it is. But you should - it is your job to learn why it is, and how to do it, every time.
This is not rocket science at all - we can of course see everything that happens in the picture result. The lighting is all there right in front of us, obvious even, so we ought to learn to just look for it. You may be amazed when you realize how much is already right in front of your face... Learn to see the light, and the gradient tonal variations. Where are the shadows? Really, is that all of them? You didn't miss anything? Look again. And again, and again tomorrow, and every day. This new seeing ability slowly builds, not overnight, and we slowly start realizing that there is more to see if we just look. We see more and more (but which was always there). It becomes easy and obvious, once we become aware. I am repeating a lot, and it is hard to describe in words, but the goal sought here is for you to realize there is actually more to see, right there in front of your face, and hoping for your determination to watch it and think about it. The actual problem is that beginners typically don't see much, until they teach themselves to look. Start by concentrating a little harder, what can you actually see?
It is considered to be very good standard classic academic portrait practice to start learning with one light and a reflector (specifically to learn about lighting, to learn to see the shading on the face, etc). A reflector can provide the fill, to modify the shadows we see. Beginners typically don't see much at first, so the first trick is to learn to SEE this lighting, to recognize what you are trying to do. A reflector may be sort of doing it the hard way (passive, only does what it can do, from where it can do it), but is about the same deal as not letting little kids use a calculator in school, to teach the principles first. And results can be absolutely excellent. An excellent inexpensive and stiff reflector is a white foam board from the craft store.
You could read a bit here: Google: one light portrait lighting
Clearly, photographic lighting mostly boils down to personal preferences, either the look you want to create, or simply the method you want to use. There are many ways it might be done, some better than others, but no one way is right or wrong (some do seem to approach wrong). It's your picture, create it as you wish. But those who have learned to observe the shadows that we can see if we look, often have different preferences than those who don't see yet. They might choose to move or re-aim a light, or to set a different intensity ratio. Lighting is simply about what we can see, and there are obvious details that we can learn to see (so practice looking, and think about it). You will see more and more as you progress, if you think to look. And if you think when you look - which is admittedly platitudes, and admittedly hard to describe, but seeing really does require practice looking, and practice thinking. If you have not started looking yet, you have much to discover.
Adding more light is easy, and is almost always better than too much dark. This illumination is the major advantage of course, and about anything is better than nothing. If the exposure is acceptable, then a cute little kid or a pretty girl will be wonderful, nearly no matter what you do. However, there is more you can do, there definitely are some subtleties too. About any weird plan you can think to try probably already has a name, and may have some fans too. But some of these methods are classics, with far wider appeal than others. Pros also have the advantage of learning what sells.
Lighting books are sometimes disappointing to novices, because they show pictures, and to get it, we have to look, and we have to see. So practice your seeing, which is much of the skill of lighting. They do say "photography is about light", however lighting is more about the shadows (the gradient tonal variations). To control it, you have to be able to see it (meaning, an awareness to notice it). There is much known lighting information online, but seeing is an awareness which involves the thinking brain.
Here are a few generalities, examples of lighting, of its initial steps, about the things we can see, which should become obvious to your seeing.
One major exception: Flat frontal light at reduced level is a very good fill light, including from hot shoe direct flash for fill flash on faces in bright sun. The fill is normally compensated to be a less intensity (a stop or more) than the ambient (the sun makes the interesting shadows, and the fill at about -1.7EV softens them acceptably). Note that this compensation is done rather different between TTL and TTL BL flash modes (Part 4).
Consider photographing a large group with two or three rows of people... an umbrella near each end of the group, aimed inward at center, provides a nice even light across the group. One light falls off toward the more distant center, but it is reinforced by the other light there. But if multiple rows, it also causes major shadows that the camera angle sees (one row on the next), and there is great risk of some faces being in the shadow of other heads.This can work well for one single row, but we get terrible shadows from multiple rows. We cannot see this from a flash until the picture is taken (tell all people they must be able to see both the camera, and the flash on that side). But bleacher steps are used to raise the rear rows, and the camera angle is raised too (maybe on a step ladder), to look down on the rows, to see all faces in the clear, but the picture still sees all these shadows from the lights.
So in contrast, another choice for multiple rows is two lights, both near and above camera position, and aimed somewhat outward, illuminates the same faces that the camera angle sees, in all cases (pay attention to any lighting center overlap).
The fill light level is frequently metered to be about one stop less (half power) than the main light (ratio, for this purpose). But the ratio of the two lights is a choice - it can be a high ratio - a weak fill, retaining dramatic dark shadows only slightly softened, for high contrast. Or the ratio can be low, more equal fill, creating a more smooth even low contrast. One stop difference is a good general value for color work. This is something we can see, and it is your preference. The degree of that fill light creates intentional lighting ratio (shadow density). This ratio is speaking of one face, we cannot hold a ratio across a group (because of light falloff with distance from flash). There are classic variations of lighting details, the names of which usually concern the shadow of the nose. For example, Rembrandt lighting, the nose shadow reaches across face to just barely touch the shadow at side of face there. This leaves a bright triangle on cheek above the shadow. I am not at the level of caring quite that much, but I know the far cheek ought to have some light on it. There are many choices, but several variations for individual portraits involve a main light about 45 degrees high and wide (from subject's nose), and a weaker fill light near the lens axis. More about ratio in this sample setup.
My preaching here is hoping to convey the advantage of learning to actually see your results. Beginners are confused because they do not see yet - they are unaware that they are missing the nuances of the lighting. Once you finally realize there is a lot more to be seen by just looking, then you will get it, and will know your preference, and how to create it. But this awareness is a troublesome beginning step which always requires conscious effort. I started clueless too, we all did. Believe me, I understand about not seeing nuthin' at first. We can spend years that way, before we wake up and look around, and realize there is more to be seen. Lighting simply requires looking, and thinking, which becomes seeing. I'm talking a lot, and beginners may scoff at this, we all think we see everything. I imagine I do too, but as you practice looking, there will come a time when you finally realize what it is about, and will understand more, and will be aware that you have become more aware. It will not be real easy, it will take time and thought, but anyone can do it if they try - just not many of us bother to try. Just learn to look, so you can see, to better know what you are trying to do. Pretty soon, you will be noticing the shadows in all the pictures you see, magazines, movies, television, catch lights in the news anchors eyes, all the visible stuff you never thought about before. A high point will be when you realize you are contemplating the lighting ratio in the scene in the movie, instead of worrying about who is the murderer.
The first new basic studio lighting concept to be grasped is short and broad lighting (look at the shadows). Simply good and important starting stuff to realize, an excellent first step towards realizing the goal of lighting is these shadows. A lighting ratio is required to create those shadows. I am trying to say - if you can look and consciously notice (see) these obvious shadows, and their differences, then you are on your way to actually seeing when you look. It is all out there for us to simply see, if we look. Then, after you see, you will know what you are trying to do.