Section 1-Types of Lights, or there s more than just bulb? photoelectric principle relies on it. You might be able to shoot a scene or location using

Transcription

1 Chapter 6- Lighting for Video Ch 6-Version 1.7 Page 1 of 20 Section 1-Types of Lights, or there s more than just bulb? Lighting is one of the cornerstones of video production, for the sole fact that the photoelectric principle relies on it. You might be able to shoot a scene or location using the available light, but that will depend on a concept called Base Light. Base Light: Even, non-directional (diffused) light necessary for the camera to operate optimally. Normal base light levels are about he 2,000 lux ( foot-candles). 1 Think of this term as a threshold. If you have a certain amount of light above this line, you re fine. But if you don t have enough light, if you re below this Base Light, it s probably going to be too dark for your camera and at that point your image becomes dark, muddy, pixilated and grainy. There is a little wiggle room depending on your camera setup in terms of OHB, lens, engineer, etc. But the fact remains, the first question you have to ask yourself is: do I have enough light to shoot here? But beyond just having light for the camera, lighting determines the mood of a scene or space. Simply altering the lights can change the entire character of a piece. Plainly put, lighting can make or break any production, so knowing how to use and work with lights directly influences your future in video. No pressure. There are nearly as many types of lights as there are words in the dictionary, but here we ll cover some of the basic types, starting with the simplest, natural light. -Natural Light: 1

2 Page 2 of 20 Figure 6.1: Examples of Natural Light (TV, Sun, Car Headlights) It s the biggest light source you ll ever work with: natural light. This is available light that s part of the scene and would be there whether or not you re shooting. This can include streetlights, TV screens, or the most obvious source of natural light, the sun! -Open Face Lights: Figure 6.2: an Open-Face light The open-face light is the simplest of artificial lights. It s literally just a hot bulb, perhaps surrounded by a basic reflector. It gets its name from the fact that it has no lens or diffusion, the bulb is literally open-faced. It provides strong, efficient light, and is usually small enough to fit into any space. The two basic kinds of open-face lights are Scoops, which have a bowl-like enclosure around the bulb, and Broads, which have a rectangular box like enclosure. The difference is typically in the bulb, with Scoops utilizing round bulbs, almost like what s in your house, and Broads enclosing longer, tube bulbs. Figure 6.3: an Open-Face Scoop Figure 6.4: an Open-Face Broad -Soft Lights: Figure 6.5: A Soft Light Next is the soft light. In this light, the lamp is reflected before coming out of the light and on to the subject. Because of this reflection, there s no lens. Soft lights are bright, but as the name suggests, soft, therefore they eliminate shadows and are primarily used as the key light.

3 Page 3 of 20 -Fresnel Lights: Figure 6.6: A Fresnel Light The Fresnel light is a staple in the film and video industry. It s easy to tell apart from other lights due to its concentric circles in the glass of the lens, which serves to soften the light. These lights were developed for use in lighthouses. Original lighthouse lenses were thick, so when the bulb burnt out, the lens wouldn t cool evenly and it would crack, requiring costly replacement lenses. Ships crashed. It wasn t a good situation for anyone. This technology has been refined and made smaller for use in our field. The Fresnel lights are sturdy, easy to use, and simple to replace if broken. -Ellipsoidal Lights: Figure 6.7: An Ellipsoidal Light Ellipsoidal Lights are lights frequently used in theater and stage lighting. These lights are kind of a combination of an open face and soft light because the light is direct, but bounded off of a mirror. After being bounced the light travels down a long barrel on the front of the light. The key factor in an Ellipsoidal light is its ability to shift the lens in the barrel, allowing the light to be focused or softened at will. -LED Lights: Figure 6.8: A Spotlight with Mr. Pixel where the bulb would be

4 Page 4 of 20 A new technology developing is LED lights. This type of light uses an array of LEDs to generate enough light for production or a show. These lights can be computer controlled to vary their color and intensity. -Bulb Type: Figure 6.9: KinoFlo Fluorescents and Tungsten Fresnels It s also important to note that, there are different types of lights, e.g. fluorescent versus tungsten, but all lights in their simplest forms are incandescent. It s the gas inside the casing that makes it different. For example, an incandescent light surrounded by fluorescent gas is a fluorescent light bulb. These bulb types burn different colors, which we ll discuss in a moment. Note: Never touch a bulb with your hand! Unlike light bulbs in your home, professional lighting bulbs are different and aren t protective coated from the oils on your skin. If you touch a bulb, when it turns on the oil will cause a heat bubble and the bulb will violently explode, which as you can guess, is very, very dangerous! Make sure to always have a scrim in front of the bulb for safety when possible. Figure 6.10: a lighting scrim -Robotic/Intelligent Lights:

5 Page 5 of 20 Figure 6.11: A Wiggle light Figure 6.12: Intelligent as used by Mr. Pixel. (Mr. Pixel running a computer attached to several Wiggle Lights that are projecting Mr. Pixel on the wall) The final type of lighting we ll discuss is the robotic, intelligent light. These are programmable lights attached to a server so they can be synchronized and instructed to move and react to the show happening around them. This type of light is often referred to as a Wiggle Light based on their patterns of movement. They even know their place on the stage and in relation to other robotic lights in the system. They create dynamic light shows that can be used to add ambiance anywhere on the stage. Section 2- Lighting Mounts, or there s easier ways to light than standing there holding it with your hands

6 Page 6 of 20 So you ve got all these lights, but what do you do with them? You can t stand there holding them during the shoot, they re going to get far too heavy and hot. Granted you could use interns for this, but you re much better off attaching the lights to mounts. Just like camera mounts in the previous chapter, there s a variety to choose from, each of which are made for a specific function/location. -Lighting Stands: Figure 6.13: A Fresnel attached to a Lighting Stand Figure 6.14: A Fresnel attached to a C-stand. C-stands are a great for mounting lights, but keep in mind that it s a universal tool and can be used for any number of purposes on different shoots The most basic mount is the Lighting Stand. These stands are very similar to tripods, except are made to have lights mounted to them. They have three extendable/lockable legs just like a tripod and typically have a height adjustable center pole. They re a very versatile tool that you re sure to run into during production. Beyond this basic type, you ll probably run into several variations, the most popular being the C- stand where the legs rotate and lock around the central pole. -Lighting Clips: Figure 6.15: An Open Face light with a built in clip Clips are another extremely simple and versatile tool for mounting lights. These clips are frequently built into the socket of open face lights and can be attached to nearly any surface, making this a great mount-choice when shooting in small, confined spaces.

7 -Lighting Clamps: Ch 6-Version 1.7 Page 7 of 20 Figure 6.16: A Light attached to a c-clamp Figure 6.17: A Light clamped into a grid Clamps are another staple of the lighting business. These clamps are the middlemen between the lights and the surface you re attaching them to. The clamp is attached to the light then attached to the surface. This is opposed to the clip, which is built into the light. The type of clamp you use will depend what you re attaching the to. There are different clamps mounting lights to batons, lighting booms, grids, trusses, just to name a few. -Safety (locks, clamps, sandbags): Figure 6.18: Lighting Stand Locks with Sandbags When working with any of these lights, you always need to keep safety in mind. No matter what the application, you re going to want to secure and weigh down your lights. There are several tools used for this, including stand locks, ratchet-locked clamps, and even sandbags to keep your light from toppling over. In addition, you never want to over-tighten any lock, clip, or clamp. Over-tightening can ruin the threads and cause it to actually fall. With this in mind, you also always want to use a Safety. These are secondary straps typically used when working with clamps that are designed to catch the light if the main mount should fail. Always use all available safety precautions when working with lighting devices that hang over the heads of cast/crew/audience. If they were to fall, it can definitely be fatal. Figure 6.19: A lighting Safety

8 Page 8 of 20 In addition to securing the lights, always keep heat in mind. As we ve said before, the only thing more surprising than how hot a light can get is how fast it will get there. Within seconds that bulb and housing will be hot enough to seriously hurt you. Always use gloves or some other kind of safety device to adjust hot lights. Beyond heat, always make sure you ve mounted your light with the right side up. This is to prevent anything from falling out, such as a gel or top hat, which we ll discuss shortly. And finally don t be dumb on a ladder. Be sure you re not climbing too high for the ladder and don t leave tools unsecured. Remember, ladder safety is not just for you, but for the people below as well. Section 3- Three-Point Lighting, or the basics You ve got the lights and you know how to mount them but how should you set them up? How can we light our subject for the camera? Three-point lighting is a basic, yet professional looking way to light your average scene. As it s name suggests, it s comprised of three lights. The first light is the key light, which primarily lights your scene. The most important rule of the key light is that it s set approximately 30 degrees off of the camera and approximately 30 degrees above the subject. If you place the key light more than 45 degrees above the subject, heavy face shadows will develop. The key light should be the brightest of all your lights. Figure 6.20: The Key Light (graphic) Figure 6.21: Key Light only on a subject The second light in the three-point is the fill light. It has the same characteristics as the key light in terms of distance from camera and subject, but this light should ideally

9 Page 9 of 20 be 90 degrees off of the key light, and at least half as bright. This light helps fill out any shadows created by the key light. Figure 6.22: The Key Light and the Fill Light (graphic) Figure 6.23: The Key Light and the Fill Light on a subject The final light is the backlight, sometimes called the rim light. It s placed anywhere behind the talent, so long as you can t see the light or the stand in the camera s shot. This light outlines the back of the talent s head and shoulders. Again, it should be half as bright as the key light, or the same intensity as the fill light. This light allows your subject to pop out of the background. Figure 6.24: The Key Light, Fill Light, and Rim Light (graphic) Figure 6.25: The Key Light, Fill Light, and Rim Light all on a subject In three-point lighting there are three lights on the subject, but the name is also somewhat deceiving, because sometimes Directors of Photography will use a fourth light. This light is called the background light. Its purpose is to light the background behind the subject. It s not included in the three-point lighting scheme because this light is pointed towards the background, not the subject. The background light is a part of scene lighting, or lighting that focuses on the space instead of the subject, which we ll discuss next. Figure 6.26: The Key Light, Fill Light, Rim Light, and Background Light (graphic) Figure 6.27: The Key Light, Fill Light, Rim Light, and Background Light all on a subject Section 4-The rest of the scene, or I need to light something besides the people? You know how to light your subject, but what about the rest of the action? When working on a live event, stage, or even wider shots on a film shoot, you re going to need

10 Page 10 of 20 to light more than just the subject you re shooting. We talked about light affecting mood and lighting the scene is a big part of that. Whether it s a poster on the wall of a bedroomscene, or the drummer s gigantic setup at the concert, the light you place on these parts of the space will have a huge impact on how the audience feels about what they re seeing live and through your camera. -Set lighting: Figure 6.28: A light in an overhead grid illuminating a set piece Set lighting is a general term used to describe any lighting source that s used to illuminate parts of the space. These can include lights physically in a scene like a desk lamp, or large lights hanging above the stage splashing onto the backdrop. -Kickers: Figure 6.29: low Kicker lights at the front of the stage A kicker is a low light placed at the front of the stage shining up. They are the modern evolution of lamps that used to be placed downstage. -Side lighting: Figure 6.30: Side lighting on the side of a stage Side lights are lighting setups that are off the stage, or outside the camera s view, but are lighting something within the camera/audience s view. Let s say you have a really important cactus right on the edge of the stage. You might use a sidelight off stage to draw attention to it, without using a light directly on stage or something as powerful as a spotlight.

11 Page 11 of 20 Section 5- Light Color Temperature, or it looks the same to you, but it isn t We ve already talked about white-balancing a camera, but you should know that your eyes can also white balance, and they typically do it without asking your permission. When you look at a light, you see white, but that s your brain white balancing for you. The camera doesn t have this luxury. This is why it s important to know the color temperature of the lights you re using. This color temperature is determined by how hot the light is burning. Lights can range in temperature color from pure-white, to blue, green, or even orange. Figure 6.31: Lights burning at different colors Figure 6.32: The Kelvin Scale of color temperature The colors of light all go back to a man named Kelvin. Lord Kelvin, actually. Kelvin was a British noble who experimented with the relationship between heat and light. You probably remember hearing his name in high school chemistry class. His research led to the Kelvin scale of measuring temperature. Kelvin: The fundamental unit of temperature. It is not calibrated in terms of the freezing and boiling points of water, but in terms of energy itself. The number 0 K is assigned to the lowest possible temperature, called absolute zero. 2 So the temperature of a light in Kelvin corresponds to what color it actually is (before your brain auto white-balances). Think of it this way: you ve heard of the phrase red hot, well there s also green hot, blue hot and even white hot! 2

12 Page 12 of 20 Keep in mind you ll always have ambient around your shoot, either the sun, a TV, or any number of other sources. It s important to make sure the color temperatures of your lights are as close to one another as possible, so there are no inconsistencies between what your camera thinks is white light. Also keep in mind that lowering power to a light changes its temperature, specifically in incandescent lights. In incandescent, lower voltage results in more of an amber color, this is why the long life-low voltage bulbs from stores burn at more of a yellow than their power-guzzling counterparts. Note: It s easy to white balance when using video, but keep in mind that if you re using film it s going to be a whole new ballgame. Light color temperatures register different on celluloid, so you re going to be ordering film stock to match the lights you re using, which is how they white-balance in film. Section 6- Using Color, or it s like painting without the mess Now that you re aware that light has color temperature, let s talk about how you can use it to your advantage! Video is obviously a visual medium and the more you keep that in your mind and creative process, the better your work will be. One of your most valuable tools in creating video is light. We ve talked about how it s what sets the mood of your scene so it s time to put that to work. Working with lights is all about painting, specifically painting what the camera sees. Figure 6.33: A DP adjusting a light We ve talked about the color temperature of lights and how to white balance the camera so those lights show as white. That s a basic rule of camera operating. What s the best thing to do with rules? Break them! Purposefully mis-white balancing a camera is

13 Page 13 of 20 one way to add color all over a scene, or even in specific points. Let s say you re shooting a living room scene that s primarily lit by daylight from the windows. If you white balance for this daylight, your scene will look correct, but if you throw a couple tungsten lamps into the mix, the camera will read them as a dark yellow, which can be used to create pools of colored light all over. Even a desk lamp that s part of the scene can be turned on to create a pocket of color. It s all about experimentation to create the look and feel you want to achieve, and as much as you read about it, it s truly one of the aspects of this medium that you can only really learn about by experimentation and dedication. Figure 6.34: A room lit and white balanced for daylight with a tungsten lamp on Beyond the actual color temperature of your lights, you can also use colored gels to create a new look. These gels are thin plastic elements that attach to the bulb housing to change the actual color of the light. It s a whole new tool to use and master with lighting! Figure 6.35: A colored gel attached to a light Note: When using gels, don t be surprised if you walk away and shortly after smell something burning. Your average gel doesn t hold heat well and will burn easily. Keep this in mind and try to not leave gelled lights on for extended periods of time. Section 7- Adjusting the Light, or ouch it s hot! Sometimes you re going to need to adjust the amount of light, or the intensity, you re getting in a scene. In situations like these, you have several options, but the one constant is that you will eventually get burnt. Lights get extremely hot, extremely fast, so it s better to just accept it now, and move on with your life. If you can find someone who

14 Page 14 of 20 works with lights who has never gotten a little burn from a light, you probably just found someone who s unemployed. Here are some simple ways to lower and manipulate the intensity of the lights you re using: -Inver Square Law: Figure 6.36: The Inverse Square law The most obvious solution to controlling light is to simply move it! Light diffuses naturally, so if you pull the light back from the subject, it will be less bright, and the opposite holds true for moving the light closer. This is known as the Inverse Square Law. Inverse Square Law: Formula stating that if you double the distance from the light source, the light level goes down by a factor of 4, if you triple the distance, it goes down by a factor of 9, and so on. 3 -Bounce Light: Figure 6.37: A Bounce Light A Bounce Light is the process of literally bouncing the light off a surface to get some extra fill light off a bright source or just to lower the intensity of a light if you can t move it back. -Umbrellas: Figure 6.38: Lighting Umbrella Umbrellas aren t just for rain anymore. If you use a lighting umbrella you can shoot the light through the umbrella to diffuse it and make it softer, or bounce the light off it and back onto the subject. 3

15 -Spot/Flood: Ch 6-Version 1.7 Page 15 of 20 Figure 6.39: Spot/Flood Settings Lots of lights will have two settings: spot and flood. The spot setting is harsh and very directional, pointing to your subject, while the flood setting is a bit softer, and literally floods the scene with light, rather than pointing it like the spot. A quick way to setup a backlight is to set up the light and flood it, making it less intense. -Lighting Scrim: Figure 6.40: A Scrim Scrims are wire screens that block light passing through them. It s a simple way to dim light without shifting color temperature -ND Gels: Figure 6.41: An ND Gel We already talked about Colored Gels in the section on Using Light. But there s another kind of gel and that s the Neutral Density, or ND gel. Neutral Density gels are exactly like the ND filter on the camera, they dim lights without shifting color. -GoBos/Flagging: Figure 6.42: Flagging a light Figure 6.43: Lens Flare Figure 6.44: a glass GoBo with a pattern Figure 6.45: a paper GoBo cutting light This term refers to lighting instruments that Go Between (GoBo) your light and your subject. This term is applied to a few different types of lighting tools. The first is a metal or glass plate that clips onto the end of the light and changes the light by either

16 Page 16 of 20 modifying its intensity or adding some sort of pattern. The second type refers to hanging or mounting some sort of paper or plastic element in front of the light to adjust its intensity and direction. The final method is referred to as Flagging, which is a method of holding fabric in front of a light to eliminate lens flare in the camera. Lens Flare: It is caused when light strikes the lens and either causes the entire image to be fogged in appearance, or for a little row of polygons (the silhouette of the iris) to appear from the light hitting the surfaces of the many elements in the lens. 4 -Barn Doors: Figure 6.46: Barn Doors attached to a Fresnel Barn Doors are small metal plates around the light that can be used to dim its intensity or focus it in a specific direction. Some lights, like Fresnels, will need Barn Doors attached to the light, but others like Ellipsoidal will have them built in. -Top Hat/Snout: Figure 6.47: a Top Hat attached to a Fresnel A Top Hat (or Snout) is a device that attaches to the end of a light. It looks exactly like its name, a top hat turned on its side. The tube of the hat focuses light and fights diffusion, maintaining a circular shape with crisp edges. Section 8- F-Stops, or a whole new way to count Now that you know about light and how to control it, you might be asking yourself, how do I measure it? To truly be able to control light, you ll need a way of quantifying it, which is tough to do when you re working with light. Dim and bright 4

17 Page 17 of 20 aren t going to cut it when you re working with light. Because of this we have a few different methods of measuring light. The first of the methods is F-Stops. F-stop: A number that indicates the relative size of the opening of the lens (aperture) and written, for example, as f/16. Because the number is obtained by dividing the focal length of a lens by it's effective aperture, the larger the aperture, the smaller the f-number. In the conventional series, each number represents an aperture that admits half as much light as the preceding one. Thus f/16 lets half as much light as a lens opened to f/11. 5 Figure 6.48: F-Stops on a lens As the above definition and title of the section explain, f-stops are a whole new way of counting with light. Instead of just setting the light to 1, 2, 3, or 4, you re going to count using f-stops for your exposure. For instance, instead of 1 through 4, you might count F-Stop 1.8, 2.4, 3.5, 5.6. The order of the stops will depend on your lens. So now when someone says that a light needs to go down by a stop, you know you need to dim the light by one stop of exposure, say from f/5.6 to f/3.5. You ll most often run into F- Stops on film production sets. But in the theater/live event world, the Foot Candle is the dominant measurement. Foot-candle: A measurement of light reflected by a surface one foot from a lighted candle. Candle light is measured in lux and is commonly used as a light measurement for LCD displays and projectors. 6 Figure 6.49: A graphical representation of a foot-candle As the definition states, a foot-candle is basically what its name describes, it s the amount of light a candle could produce over a 1 square-foot area. It s sort of like the =1

18 Page 18 of 20 horsepower of lighting. Typically on TV broadcasts, you ll be shooting for around 150 foot-candles of light. So you know the various types of measurements you ll run into, but you ll still need an actual tool to do the measuring. You know how long one foot is, but you wouldn t want to eyeball-measure it, would you? The same logic holds true in video, you don t want to eyeball-measure your light. The tool you ll use in this situation is a light meter. Figure 6.50: A Light Meter A light meter is a tool that measures the amount of light falling on an object and can turn that measurement into an exposure or calculation in foot-candles. It s an invaluable tool when working with light. You ll use it in two different ways. The first of these is measuring Incident lighting, or the amount of light that falls on the subject. The second type is Reflective lighting, or how much light is being reflected off your subject and back into the camera. You ll measure Incident lighting off of the subject itself, and Reflective lighting off of the camera lens. Section 9- Power, or lights aren t much good without it You re going to need electricity for lights. Sorry, there s no getting around that. But what you need to know is how much power you ll going to use, or how much you have to work with. Too many lights on a circuit will blow a fuse. This stops production and slows everyone down for a mistake that could have been avoided. On your average household circuit, you ve got approximately 15 amps to work with, and roughly speaking, your 600 watt light requires 5 amps, so three lights is the most you ll get on that circuit safely. Keep in mind, there s not one circuit running to

19 Page 19 of 20 each outlet. Frequently outlets that are close to one another, or on the same wall, are on the same circuit, so don t overload it! Just because you have four outlets, does not mean you can plug in four lights! In this case, you ll learn to love extension cords. Note: In school and industrial settings, like here at Purdue, there tends to be a dedicated circuit for water coolers, like drinking fountains, so if you re in a pinch, unplug the fountain and use that circuit for lights. Note: As we ve said before, power is nothing to mess with. If your video cable isn t right, there s no picture. If your audio cable is wrong, there s no sound. If your power isn t right, people get hurt and die. Always leave power to those with experience. Section 10- Digital Lighting, or Lighting and Video can be best friends In the last chapter we talked about the future of camera mounts, and lighting is no different. Computers and other digital technology are doing amazing things in the lighting world. As the technology evolves, lighting continues to move outside the bulb and into new frontiers. Let s talk about where the world of Lighting and Video are coming together. Video itself is moving into the lighting world. Modern display technology allows the actual video to be used as an illumination device. Modern screens and projectors have evolved to the point that a graphic or video can be used to light a scene or an event. This is called Convergence, or the idea that new technology is bringing several types of technology together under one umbrella. These new types of video-based lighting can include MiTRIX systems, Versa Tube, etc. Beyond just the panel array, servers have begun to cross into the lighting world. Media servers with thousands of graphics patterns and pre-made clips are finding

20 Page 20 of 20 themselves connected to projectors and these images used as a lighting source at some events. It s all part of Convergence. So that s the basics of lighting and should be able to cover you regardless of the type of shoot you re working. By now you know how video works, how to run a camera with proper cables, and how to light a shoot. It s finally time to talk about where that signal goes after the camera: the control room. Figure 6.51: A MiTRIX panel lighting a room Figure 6.52: A Versa Tube system