Multi-light setups

Learning goal

By adding a second and a third light beside the key light in a portrait, you will be able to build three-point lighting, in which each light adds a separate job to the photo. You will explain that the key light decides the shape and the exposure, the fill light opens the shadow side, and the back light separates the subject from the background; and you will build these three lights in layers, turning each one on and off on its own. You will recognize and prevent the double shadow that forms on the face when you put the fill light in the wrong place, and block the back light from flaring into the lens with a flag or a grid. By applying the same logic to a group of four people, you will learn to bring the key light to everyone equally in group lighting, and check that every face and every edge stays readable in a group made up of different skin tones.

The question

The band's four members want a frame together for the inside cover of the new album. They line up side by side in front of the studio's dark gray background; all of them are dressed in black and navy. You set up a single large softbox in front of the group, from the left. In the test frame all four faces are lit, but the hair, shoulders and arms have merged with the background behind. There aren't four people, but four faces floating in the darkness. The faces of those on the right are also noticeably darker than those on the left.

In the corner of the studio stand two more small flashes and an umbrella. It occurs to you to put one behind the group and the other beside the camera, but you don't know where, or at what power. Every new light means a new shadow. What do a second and a third light add? In which situation do they solve a problem, and when do they create a new one?

Context

We saw that you can build most of a portrait with a single light and a reflector; we also noted that there are concrete problems a single light can't solve (Lesson 20.1). Black hair blending into black paper, a deep shadow side the reflector isn't enough for, lighting more than one person evenly are the most common of these problems. An additional light gives a separate answer to each of these problems.

The most taught pattern of studio lighting distributes these answers among three separate lights. This pattern isn't a recipe, it is a division of labor: each light has a single job, and as long as you know which light does what, you can change the pattern however you like. This lesson tells how to build this division of labor and apply it to a group photo; the details of hair and rim light and of the background will be taken up in the coming lessons.

Simple explanation

What is each light's job?

Three-point lighting is the classic lighting pattern in which each of three sources, building the shape, opening the shadow and drawing the edge, is given a separate job. The key light, as you met in earlier lessons, gives the face shape and decides the exposure; the whole pattern is built around it. The fill light, on the other hand (Lesson 18.3), is the second source, kept weaker than the key light, that opens the half left in the dark; it does the reflector's job with its own power and to the degree wanted.

A back light is light that comes from behind the subject, usually from the side opposite the key light and from above, and separates the subject from the background by lighting the edge of the hair, the head and the shoulders. It doesn't light the face; it draws a thin, bright line around the subject. When a black jacket or dark hair moves in front of dark paper, what separates them from each other is most often this line. Many patterns also add a fourth light, a background light that lights the background separately.

The power of each light is set independently of the others. The difference between the key light and the fill decides how shaped or flat the face will look, while the back light's power decides how distinct the edge line will be. The back light is usually used at a setting similar to the key light or a little stronger, because hair and clothing most often reflect less light than the face; but the right power is always decided in the test frame.

How are the lights built?

Building in layers is building the lights not at the same time, but by turning them on one at a time and judging each one on its own. First you turn on only the key light, and get the face's shape, its shadow pattern and the exposure right with it. Then you turn off the key light and turn on only the fill, look at what it does to the face, and then turn the two on together. You try the back light the same way, first on its own, then together with the others.

This method shows clearly which light produces which shadow and which shine. Turning all the lights on together and trying to fix the result makes it harder to find the source of a problem; you can't fix a shadow or a shine without knowing which light it comes from.

A double shadow is two separate lights casting two separate shadows on the face or the background; its most typical form is two shadows of the nose falling to both sides. If the fill light is put on the side opposite the key light and at a power close to it, it produces its own shadow and two shadow systems overlap on the face. The way to prevent this is to place the fill close to the camera, near the lens axis, as a large source. In this position the fill's shadow falls largely behind the subject and the lens doesn't see it. Keeping the fill's power a few stops behind the key light also makes its shadow invisible.

Because the back light looks toward the lens, it carries a danger: if its light enters the lens directly, flare and a loss of contrast form in the photo. Attaching a grid in front of the back light, or putting a small black flag between the lens and the back light, makes sure the light falls only on the subject's edge.

How is a group lit?

Group lighting is lighting more than one person in the same frame at a brightness close to each other. When lighting a single person, putting the key light close to the face gave a soft light; but in a group, the person standing close to the key light comes out much brighter than the one far away because of the inverse square law. Moving the key light away from the group shrinks the difference in distance between people and evens out the brightness; and for this, a larger source is needed to keep the light's softness.

Feathering the light also works for groups. Aiming the softbox's center at the group's farthest person makes the light reach the people close by more with its edge zone; the extra light from the center falls on the far one, the lesser light from the edge on the near one, and the brightness balances out. Lining the group up at roughly the same distance from the key light, in a slight arc, does the same job. The back light, on the other hand, most often goes up to two in groups; one from the right, one from the left, drawing the edge of all the heads.

In a group of mixed skin tones, the key light's exposure needs to make every face readable at the same time. The bright areas on a light-skinned person's face shouldn't blow out, and the midtones and shadow side on a dark-skinned person's face shouldn't be lost. Feathering and fill work together here: the fill opens all the shadow sides a little and keeps detail on dark skin, and feathering can shift the brightest area of the key light off the light-skinned faces. When a dark-skinned, dark-haired musician stands against a gray background, the edge the back light draws is the main tool that separates them from the background. In the test frame you need to enlarge each face one by one and check the detail and the edge.

Visual evidence

In the studio you pull the key softbox two steps back from the group and raise it, and turn its center toward the bassist on the far right. In the frame you shoot with only the key light on, the four faces are now close to each other in brightness; on the light skin of the drummer on the left the forehead doesn't blow out, and on the dark skin of the bassist on the right the cheeks and eyes can be made out. But the shadow sides are deep and the hair is still merged with the background.

You turn off the key light and put a flash with an umbrella right beside the camera as the fill, setting its power two stops below the key light. When you turn them on together, the shadow sides open slightly; in the first try, when you put the fill to the right, opposite the key light, you had seen the noses cast two shadows to both sides, and now that second shadow isn't there. Finally you place the two small flashes behind the group, to the right and the left, aimed down at the heads, and attach grids in front of them. A thin, bright line appears around the four heads and shoulders; the bassist's dark hair and navy jacket now separate from the gray background. The four people are no longer faces floating in the darkness, but four people together.

Common mistakes

Summary

In three-point lighting the key light decides the shape and the exposure, the fill light opens the shadow side, and the back light separates the subject from the background by drawing its edge; the power of each light is set separately, and the pattern is built in layers, each light turned on and judged on its own. If the fill is put opposite the key light and at a power close to it, a double shadow forms; a large, weak fill near the camera prevents this, and the back light flaring into the lens is blocked with a grid or a flag. In groups the key light is moved away and feathered to reach everyone equally, back lights draw the edge of all the heads, and in a group of mixed skin tones each face's detail and edge is checked one by one.

Mini assignment

If you don't have three lights, you can build the same division of labor using a reflector for the fill and a desk lamp or window light for the back light.

1. Shoot a person with only the key light; then turn off the key light and shoot with only the fill, then with only the back light; finally turn all three on together.
2. Shoot two frames putting the fill first opposite the key light, then beside the camera, and find the double shadow.
3. Shoot the back light first without a grid or a flag, then with a flag; see the difference in the flare entering the lens.
4. Shoot a group of two or three people with the key light first close up, then far away and feathered; compare the brightness difference between people and record the setup with a lighting diagram.

Check yourself

• Looking at a photo, can you tell which shine and which shadow comes from which light?
• Can you state the cause of the double shadow and two ways of preventing it?
• In the group frame, did you check that every face and every edge stays readable by enlarging them one by one?

Glossary

Mini quiz

1. What is the back light's basic job in three-point lighting?

• A) Opening the face's shadow side
• B) Deciding the exposure
• C) Changing the background's color
• D) Separating the subject from the background by drawing its edge

2. What happens when you put the fill light directly opposite the key light and at a power close to it?

• A) The face's shadows are erased and it turns into a bright white flatness
• B) A double shadow forms on the face
• C) The background lights up
• D) Red-eye appears

3. What is the way to reduce the person standing close to the key light coming out brighter in a group?

• A) Moving the key light away from the group and using a larger source, or feathering it
• B) Bringing the key light even closer to the group
• C) Opening the aperture
• D) Removing the back light

4. When a dark-skinned, dark-haired person stands in front of a dark background, their hair and shoulder merge with the background. Which is the most fitting solution?

• A) Bring the key light one step closer to the group
• B) Remove the fill light
• C) Draw the edge of the head and shoulder with a back light fitted with a grid
• D) Change the white balance

Answers

1. D — The back light lights not the face but the subject's surroundings, and separates it from the background.
2. B — A strong fill from the opposite side produces its own shadow and overlaps with the key light's shadow.
3. A — With a receding light the difference in distance between people shrinks; feathering also gives the near one less light.
4. C — The edge the back light draws is the main tool that separates dark hair and clothing from a dark background.

Summary card

• Key light for shape and exposure, fill for the shadow side, back light for the edge and separation.
• Build the lights in layers; judge each one on its own.
• Move the fill near the camera and keep it weak; prevent the double shadow.
• A grid or a flag on the back light; don't let it flare into the lens.
• In a group, move the key light away and feather it; check each face and edge one by one.

Bridge to the next lesson

In the group's frame, when the back lights drew a thin line around the heads, what stood out most was the bassist's hair: every strand of their curly, dark hair glowed like a bright ring. But when you turned the back light up a little too much, that ring turned into a bright white crown and spilled over to the side of their face, making their cheek shine too. Why is the hair shining? The next lesson tells about the angle and power of hair and rim light and how it behaves on different hair textures.