Okay, so now lets take a look at how you can light a scene or an interview. As I said earlier, all lights have different colour temperatures, so you should look into what you are using, and how they can work together. For example, you might not want to mix a tungsten 5k with a fluoro softbox, unless you want a difference in colours in different parts of the scene.
Before we get into lighting setups, another piece of fascinating theory!!
Okay, so this is an invaluable piece of physics that at first can seem a bit daunting, but is really pretty simple, and fairly obvious too when you think about it. The inverse square law is relevant to electricity, magnetism, sound, radiation and light. For film and photography lighting it is a way of understanding the fall-off of light as it moves away from a light source. If something increases in a square, then if it were to start at 1, it would increase to 2, then 4, then 8, then 16 and so on and so forth, doubling at each interval, and increasing exponentially. With an inverse square, it does the opposite, decreasing from 1, to ½, to ¼, to 1/8, and so on, so forth.
In this case, it halves at each interval. This is how light decreases over distance, for each unit of distance the intensity of the light will be half as much as the unit before. So at two metres away from your light source the amount of light reaching that point will be ½ as much as at 1 metre, and at 3 metres it will be ½ as much as two metres, and ¼ as much as 1 metre. This means that the most largest loss of light comes closest to the source, and then slowly dissipates as it gets further away.
This becomes important when you consider the relationship between the lights on your subject and on your scene. If the light is further away, the difference in the amount of light on your background and your subject is not as large. As you move the light closer, the amount is more noticeable. As such, the distancing of your lights plays a large role in how powerful they are relative to eachother, but also how much light is cast on your background and what your contrast ratio is.
This can be especially helpful to understand if you are trying to achieve a black background for interviews. To do this it is important to create a large difference in the lighting in the foreground and background, and to achieve this, we want to move the lights as close as possible to the subject, and the subject as far away from the background as practical. While all this math can be a bit confusing its great to have this in your head when your playing with lights. It can help to explain why one light is performing differently to another that is mechanically exactly the same, or help you to cut light from unwanted surfaces. So next time you think, “I need a more powerful light!” maybe just try bringing what you’ve already got a little closer?
One foundational technique for lighting is called ‘3-point lighting’, and it is very popular, and also quite versatile. 3 point lighting is a basic setup to light talent, an interview or an object. Basically, whatever your focus is, you can apply three-point lighting to it. 3 point lighting involves the use of, (surprise surprise) 3 lights. The lights can be, but don’t have to be, different types of light(for example a Fresnel and two redheads, etc. etc.), but the main difference is in how the lights are used.
So the first light is the key light, we use this light to illuminate the main features of the face, or whatever it is that interests us most. The key light should be the strongest light source, but don’t worry, if all your lights are the same, just move the key closer to your subject. In a 3-point lighting setup, the key is placed just to the left, or the right of the camera, facing the subject. The key light should be facing the subject, just a little above eye level, so that it doesn’t cast deep shadows into the eye sockets, but not straight at eye level, so that some defining shadows are cast. Many setups consist of just one or two lights, and maybe a reflector, and if you are only using one or two lights, you can bet one of them will be used as a key.
(Diagram) (Example of the key light by itself)
Just using a key gives us a very contrasty look. This can be great, and playing around with deep shadows can be very evocative, but for this shoot we want nice even lighting so we can see the face.
The fill light sits on the opposite side of the camera to the key light, and is intended to fill out some of the shadows thrown by the key. It is generally a less powerful light than the key, and playing around with its distance (or dimmer) can give you differing amounts of contrast between the key and the fill. The difference in amount of light cast on the subject between these two lights is often referred to as the contrast ratio. If your key is casting twice as much light then you have a contrast ratio of 2:1. The more contrast, the more dramatic, the less contrast, generally the ‘safer’ and ‘flatter’ the image. If the light is too even the image can begin to look flat, but if you want an evenly lit subject you can experiment with giving the subject form by using a…
The back light, or sometimes referred to as a hair light, is a light behind your subject, usually directly opposite your key, used to cast a rim of light around your subject, making them ‘pop’ from the background. This light really helps give a sense of form, and can be used subtly, or dramatically, to great effect. This light can also be used to shoot highlights through the hair, hence the name hair light. Backlighting anything gives it a sense of form (think silhouettes) and is a great way of drawing attention to something with an interesting shape or form.
So those are your three lights. They don’t always have to be used in a 3-point setup. They can be used together, separately, with a 1, 3 or 100 light set up. The key is to understand what the purpose of each light is, and then you can start to get creative with what you want to achieve, and the minimum, or maximum you can use to get there.
Sometimes it can be hard to see exactly what a light is doing, so to get a better idea, try turning the other lights off to isolate exactly what each lights purpose is.
Keep in mind this basic setup does not cover lighting your background, and you may want to add one or more lights, or practical lights to fill out the background.
Background Lights are lights used to light the background of your scene, the amount of lights needed and the techniques used vary wildly depending on what your background is, and what you want to achieve. You may have a white background, and just want to shoot a line of coloured light across it to give an interview more style, or you may want to bring out the detail in the environment behind your subject. If you remember your basics of three point lighting, then you can use what lights you have left to try and give shape to your background.
Practical lights refer to lights that are used that appear within the scene. For example, a lamp that your character uses to read may also be used to light his face. Or the ceiling light swinging about could be used to create a dramatic look. A street light might create some nice pools of light in your scene. Practicals can also be lights that you have found on location and are making use of. Practical lights are a great way of tricking your audience into believing in your story. By placing a light in your scene, say a desk lamp, and then using another more powerful light, to cast light as if it was from the desk lamp, you make the audience believe in your setup, and buy into your story more. It can help the audience to forget about the artifice of film-making (or remind them when done poorly).
These small colourful lights helped create a party mood. Ok, so we did most of the re-colouring in post. Sue us.