How to Use Flash pt. 2 – Lighting Concepts and Strategies

Where to Start

How every photographer approaches lighting is a little different. The one thing we all have in common is that we start with an end goal in mind. Notice I didn’t say ‘the end goal,’ but rather ‘an end goal,’ You need a place to start, but it’s important to keep an open mind and be ready to pivot if another idea presents itself.

Just because you want to start doing one style, certainly doesn’t mean that’s where you have to end up.

Controlling Light

There are 3 ways to control light. You can add light, subtract light, or reflect light.

Adding light is done with an artificial light source, such as a flash or LED. This is very straightforward. You are introducing another independent light source to the scene.

You can subtract light by placing objects in the scene that block light. Black poster board, for example, placed next to your subject will block any light coming from that direction. Subtracting light does not necessarily mean removing a light source. It can also mean preventing light from affecting the scene. You can also use a scrim, which is a translucent piece of fabric that reduces the amount of light that passes through rather than totally blocking the light.

Lastly, reflecting light is a way to repurpose light that is already in the scene. By placing reflectors in the scene you can add light that is brighter than the shadows but not as bright as the highlights. This reduces the contrast between highlight and shadow and is often used to brighten a subject’s eyes or under their chin. You can also use walls or the side of a building to reflect light back onto your subject.

Knowing where all light in the scene comes from, you can better control your images.

Building Your Lighting Setup

Every light in the scene must serve a purpose. It is up to you as the photographer to either add light or remove light from your images. Use light and shadow to show and hide specific elements, and to create depth. Use them to create the mood of the scene.

The Key light/Main light is the primary light source in your photo. This is the light source that shows your subject. It is generally the brightest light and has the most impact on the subject.

A rim light/Kicker is any light that makes your subject stand out from the background or foreground. If your client has dark hair and is against a dark background, it is important to have a kicker on their hair so it doesn’t blend into the background. The kicker can either illuminate specific parts of the subject or the background.

The background light properly illuminates background elements, or whole sections of the scene. You can use as many or as few background lights as necessary in a shoot. A background light is not always needed.

A fill light is a less powerful light source that is used in addition to the key light. It adds a small amount of light, that is not as bright as the key light, but brighter than the shadow areas to reduce contrast in the photo. Reflectors are often used as fill lights since the light the reflected is always less bright than the original light source.

Ambient light is the natural light that exists in a scene, usually from the sun or overhead lights in a room. This can either act as your background light or your key light if you so choose. Having the sun behind your subject will light them from behind, which is called ‘backlighting.’ This is an example of using the ambient light as kicker. Or you can use flash to overpower all ambient light and avoid seeing any in the photo whatsoever.

How to Describe Light

There are many variables to consider when we describe lighting. We describe the amount of light, the quality of light, the variance between the highlights and shadows, and the overall brightness of the image. By knowing how to describe each of these variables, you can design your lighting setup to accomplish the objective of the shoot.

Quality of light

Quality of light describes the transition from the highlights to the shadows. Light is either described as hard or soft, which are both relative terms. There is no numerical value used to describe how hard or soft light is. It’s like hot and cold. There is no single temperature that officially crosses over from hot to cold. You can just feel something and decide if it is hot or cold. That’s how we qualify the quality of light.

The quality of light is determined by the size of the light source in relation to the subject. The smaller the light source the harder the light. The larger the light source, the softer the light.

Hard light means the transition from highlight to shadow is very short and abrupt. When you stand outside in the middle of the day and your shadow is a very clear silhouette of yourself, that is an example of hard light. Shadow puppets are also an example of hard light. Hard light is good for fashion, since it creates more defined shadows that show detail in texture. This also means that it will show wrinkles in skin and clothes more clearly. It is not always flattering for people’s faces.

Soft light means that the transition from highlight to shadow is more gradual. When you are outside on a cloudy day and your shadow is just a slightly dark fuzzy spot on the ground, that is an example of soft light. Soft light creates less-defined shadows and is good for reducing the appearance of wrinkles in skin.

Remember that the quality of light is dependent on the size of the light source compared to the subject. So while the sun may be considerably larger than your subject, it is very far away which makes it appear relatively small. The sun is a small spot in the sky, which  makes it a small light source. Don’t confuse size for power. It is obviously a very powerful light source, but it’s very small in relation to your subject. However, on overcast days, with no direct light coming from the sun, the entire sky acts as a singular light source, which gives us really soft light. Instead of one small spot providing all of the light, the entire sky is providing light. It’s like a giant soft box. 

When you use a soft box you are increasing the size of your light source and thus softening the light on your subject. However, if you move the soft box back, farther away from your subject, you are essentially shrinking the size of the light source in relation to your subject. So the trick is to get the soft box as close to your subject as possible in order to get the softest light. But if the light is too soft, you have the option to move it back.

Another way to get soft light is to bounce light off a larger object. If you are using a speed light on top of your camera, you can aim it at the ceiling or at the wall next to you instead of aiming it directly at your subject. Then when you take a photo, the flash will bounce off the ceiling or wall and it will act as a much larger source than the small flash on top of your camera. You can also aim your flash at a large reflector or into a V-flat (two 4’x8’ pieces of foam core taped together to make a giant V shaped reflector) to get a much larger light source. When you aim your flash at a reflective surface that large, it acts like a giant soft box and give you extremely soft light.

Color Temperature

Believe it or not, all light has a specific color to it. When light is pure white, it is daylight balanced. This means that it is the same color as the natural sunlight we see outside on a sunny day. Light can also be cool, like we see on a cloudy day, or it can be warm, like we see at sunset. This value can be measured and we use a specific number range to identify the color temperature. It is measured in degrees Kelvin.

Daylight: 5500 degrees

Overcast light: 6500 degrees

Shade: 7500 degrees

Tungsten bulbs: 3000 degrees

Fluorescent bulbs: 4000 degrees

Sunset: 2500

Candle light: 1900

Since different lights have different color temperatures, it’s important to know what those values are so you can either add a color cast to your image, or prevent it.

You can either choose the right light source to achieve the color you want, or you can add a gel to the light to change it’s color. A gel is just a colored piece of plastic that is placed in front of your light, either inside or outside of the light modifier. Gels are available in just about every color you can think of, and everything in between. This allows you to add a sunset warm light to a scene to create the illusion of the setting sun. Or you can add red, green, or purple lights to a scene for a more creative effect. Gels are also used to make all light sources the same temperature in a scene. Having a white light and a warm light in the same image might not look right. With gels, you can warm up the white light or cool down the warm light to make all light in the scene consistent. 

Since gels can be added over your light modifiers, you can still use your soft boxes or grids and control your color temperature.

Short light vs Broad light

There are two approaches to lighting someone. Your key light can either illuminate the side of your subject facing the camera, or the side facing away from the camera. This is a powerful concept to understand for many reasons.

Lighting the side that faces away from the camera is called short lighting. When you short light someone, you are putting most of their face/body in shadow, which creates a strong slimming effect. This is a great way to make people appear slimmer without using photoshop. Broad lighting is lighting the side that faces the camera and will highlight more of a person’s body and face. This can be helpful when your subject is already slim. Short lighting someone who is already very slim will make them look unnaturally slim. Broad lighting is also great for shooting fashion. It shows more of the outfit.

Short lighting also creates drama in your images. By hiding most of a person or object, you are leaving the rest up to the viewer’s imagination. This creates mystery. It’s a more subdued look. When you broad light someone, they appear more assertive and prominent.

High key vs Low key

This is another way to approach your lighting setup. Do you want a scene that is mostly lit, with strategically placed shadows to define the different parts of the scene, or do you want it mostly dark with specific highlights that give everything shape.

A low key setup has most of the image in shadow. The lighting is very directional and precise. You are only showing specific parts of the scene that you want your viewer to see.

A high key setup has most of the scene well lit. The light covers everything. It is still somewhat directional, though, as shadows are used to create depth in the scene.

Directional light

Do you remember the movie posted for the original Exorcist? It showed a man standing under a streetlight that lit him very dramatically against a dark scene. That is a great example of directional light. The location of the light source is very obvious when you see how it lands on the subject. Now imagine a swimwear photo taken on the beach in the middle of the day. There is light everywhere, coming from the sky, bouncing off the sand… There is no obvious location of the light source, therefor it is not directional.

Another example of directional light is a classic movie scene with someone walking off into the sunset and their shadow is stretching out among the road behind them. Due to the hardness of their shadow, and the exaggerated distance it stretches out, the light source is clearly in front of the subject. The Beatles famous album cover with all 4 faces lit from one side is another example of directional light.

Histograms and dynamic range

The histogram is a graph that shows the 256 values of grey between black (0) and white (255). It is broken up into 4 main sections: blacks, shadows, highlights, whites.

This chart can be helpful for a few reasons. Firstly it shows if you have underexposed or overexposed parts of your scene beyond what your camera can register. Cameras have a threshold called dynamic range, which is the span between the darkest value it can see before the pixel is registered as black and the brightest value it can see before the pixel is registered as white. Different digital sensors have different dynamic ranges. Some have a broader ranges and some have a narrower range. This range is what you see on the histogram. So when a value hits 0 it is absolutely black and when it hits 255 it is pure white.

Ok great. Why do you need to know this? A histogram tells you if you have underexposed part of the scene and the shadows are totally black, or if you have overexposed and the highlights are totally white. This is called clipping. When they hit black or white, you can not pull detail out of those pixels when you edit the photo. They are stuck at black or white. If they are dark but not black, or bright but not white, you can adjust them to bring our more detail in the image. Here’s some photo lingo for you: the parts of an image that have turned pure white are considered ‘blown out’ or ‘hot.’ The histogram tells you this information as shown below. This will allow you to adjust the light in the scene during the shoot so you can save the detail in the shadows and highlights.

Sometimes you do want clipping. If you are shooting a high key scene and want a pure white background, you want to clip on the whites. If you are shooting a low key scene and want the background to be totally black, you want clipping on the blacks. Most digital cameras have a setting that will show if you are clipping in either the blacks or white. When you view a photo after you take it, the parts of the image that are clipped will be flashing black and white. This way you can identify which areas of the images are clipping so you know what to adjust.

Histograms also show you how much contrast is in the image. When the histogram looks more like a single bell curve, there is very little contrast, and when it looks like a wide valley, there is more contrast in the scene.

What next?

Take a look through a magazine or some galleries online and start trying to figure out how many lights are in a scene, and how they're used. Which one is the key light? Did they use a rim light or a background light? Is it hard light or soft light?

You'll start to notice patterns in lighting and once you see some of the setups I've prepared in part 3 of this series, you'll be mastering this in no time!

About the Author Mike Lloyd

Mike is the Tim Burton of photography. He tells powerful, imaginative stories with cinematic photography. He specializes in dramatic, film-noir style boudoir and epic cinematic portraits. He's also the creative force behind Photogs Unite! which focuses on learning from professionals outside the photography industry to learn marketing, sales, branding, and everything else you need to know to build a thriving photography business. And burritos are the key to his happiness.

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