The human eye is an amazing recording device — used in conjunction with the brain it can squeeze detail out from the tiniest amount of light. Recording devices like video cameras don’t have this luxury and must be provided with enough light of the proper kind in order to deliver the desired visual result. Regardless of the type of lighting, basic lighting patterns and techniques, honed through countless years since the first days of photography, still apply. It's important to keep in mind that the purpose of lighting is not to call attention to itself, but instead to illuminate what is to be shot in such a manner as to create, enhance or amplify what the cinematographer is shooting.
There are many types of lighting, but some basics permeate throughout. These involve what the light source is made of, but also variables that apply to the quality of the light itself. And since video recording devices must take all of these factors into account, it makes sense to first delve into those aspects that involve the characteristics of the light.
Hard and Soft
In general, lights can all be placed in one of two categories: hard or soft. At its most basic, a small light source relative to the subject will cast strong and distinct shadows and be of high contrast. This would be considered a hard light, while a light source that wraps around the subject due to its being bigger compared to the subject will be soft and create indistinct shadows and low contrast. So why is the light from the sun on a hot summer day so hard? Because for all its size, the sun is very far away and small in the sky relative to Earth. Of course should there be cloud cover, then the lighting becomes diffuse and everything becomes soft.
Regardless of the type of lighting, basic lighting patterns and techniques, honed through countless years since the first days of photography, still apply.
Another factor to keep in mind is that the closer a light source comes to the subject it is illuminating, the softer the light will appear. This is true regardless of the light source being used. Hard light, by nature, will be found in incandescent lights or electronic flash, while soft light can be created by taking hard light and using diffusers or soft boxes to diffuse the light and is also a common quality of LED and fluorescent fixtures.
Lux and lumens are an important to understanding how light functions and how to apply it toward shooting. To simplify, a lumen is a unit of light measurement that is used to compare the total amount of light output from an emitter of light, while lux is a unit of measurement for a given area’s amount of light output, or light intensity. Where this gets practical is in application: a camera’s lux rating indicates the minimum amount of light or low light sensitivity for producing a quality picture, for example.
Color temperature refers to light’s color characteristics as measured in degrees of Kelvin (K). The Kelvin scale imagines a black body object such as a light filament that begins to glow and as it gets hotter the color of the emitted light changes, moving from first deep reds to oranges and yellows and finally up to blue or white. In imaging, light sources of varied temperatures exist. At around 2900K are tungsten lights, which become “warmer,” or (counterintuitively) drop in color temperature, as they age. The 3200K range accounts for tungsten halogen light, with fluorescents being around 4500K. Sunlight is generally considered to have a color temperature of around 5600K, but shade and skylights reach higher temperatures. These numbers are basically averages that were found to be most useful in the days when film was king — they related to the reactivity of the different emulsions. For practical use as relates to perception of color by humans from a psychological point of view, not temperature, light can be described as being “warm” (yellowish) or “cool” (bluish) as differentiated by different light sources. The appearance of the light is acted upon by the human brain but not recording devices, and so the light’s “look” must be planned for in order to achieve the desired effect.
Measuring Color Quality
There is an important measuring yardstick called the Color Rendering Index. Known as CRI, it takes a light source and quantitatively measures its ability to reproduce colors of objects in comparison with that of an ideal or natural light source. Long ignored by incandescent light manufacturers due to its being a difficult metric for matching replacement bulbs, LED lights with a high CRI are worthwhile replacements for incandescents. Most quality LED lights will have a score of 90 CRI or hight. The main negative here is that the perception of LED lighting as noted by CRI can appear incorrect — a low CRI of 25 for an LED bulb appearing to have vivid white light while a high scoring one can look poor at reproducing reds and skin tones.
There is an alternative for CRI known as TLCI (Television Lighting Consistency Index) which, while not approved as an industrial standard, is finding acceptance among manufacturers as a way to address the many issues affecting LED lighting use in film and TV production. It uses a spectroradiometer to take a measurement of the spectral power distribution of a luminaire. The performance of the luminaire, in the context of television, is analyzed and given a number for 0-100; 85-100 being errors so small a colorist ignores them; 50-75 being where a colorist would want to correct colors; 25-50 which would require color correction work; 0-25 wherein color rendering is so poor as to probably be unusable for broadcast. Unlike CRI, the scores are more spread out and so are more accurate, making the decision as to what to do less a matter of perception.
Tungsten Lighting Options
Lighting technologies have changed over the years, but instead of new methods replacing the old, we have seen more and different types of lighting supplementing what’s already available. Previously the industry standard, tungsten lighting basically consists of a bulb containing a filament made of a metal tungsten element that glows. While it can be extremely fragile, depending on the situation, these lamps were the mainstay of photographers and filmmakers and continue to be used, even with the advancements in lighting technology.
Tungsten lamps designed for professional use have a color temperature of 3200K but can be varied through the use of gels to reach different color temperatures, such as that of daylight. These gels can be had in color correction filter kits (also referred to as color rendering kits) and which provides filters for boosting the color temperature of tungsten/warm light sources, warming up daylight balanced sources like strobes, HMI’s and LED’s, balancing the green spiking from fluorescent lights and removing the green content from inexpensive light fixtures — i.e., some LED and fluorescent panels. The obvious downside to using tungsten is the heat generated by the lamps, but on the positive side the bulbs themselves are reasonably priced, available pretty much everywhere and easy to control through reflectors and other accessories that direct their light in the desired direction.
An example of today's modern tungsten lighting kits would be the Interfit 750-X Two Floodlight Umbrella Kit, which retails for $271. There are six bulbs of 250 watts each, with both of the fixtures having variable power controlled, fan cooled modules to handle the up-to 750 watt maximum allowed. Two 36-inch translucent umbrellas are included, as are stands and a kit case, and the 3,250 watt lamps in each fixture are color balanced to 3,200K and can be individually controlled from switches on the unit's rear. Featuring “S” type bayonet fittings allows for accessories to be used for modifying the light — examples being softboxes or a beauty dish for portraiture/fashion.
Another example is Lowel's Pro-light Focusing Flood Light which retails for $126. It has the ability to be used as a low-level key or accent light, fill light or backlight. It features a high-intensity reflector and prismatic glass with a 250 watt 120v bulb and 5:1 focusing. Besides having access to a wide range of customizing accessories, the light can also be battery powered, should AC power not be available.
Halogen Lighting Options
An improvement on the tungsten filament comes from tungsten halogen lamps. These bulbs possess their own reflector and have quartz envelopes filled with a halogen gas. As a result, not only does the light’s color temperature remain consistent over the life of the lamp, but the composition of the lamp itself aids in increasing its overall working life. The color temperature of a halogen light is higher than that of a tungsten and so appears whiter and brighter. As a result these bulbs burn hotter and require adequate ventilation.
Halogen lights can come in varied configurations, for example, the Impact Qualite 300 V-2012 Focusing Flood Light, which retails for $235, has a 21-40-inch focusable beam pattern and outputs 300 watts at 3,100K. A 4-leaf barndoor is included, there is safety glass and a cool-touch handle allows safe maneuverability.
There is also the Lumiere L.A 100W 3200K Tungsten Halogen Video Light Kit that retails for $100. Battery driven, the video light weighs in at only one pound and its universal screw type makes it compatible with most camcorders and provides a 100 watt light output that is easily transportable. The color temperature is 3,200K and includes a rechargeable 12V 7A MF battery. A charger and bag is also included.
If you need lots of light to fill a space, Smith-Victor offers their 1,000-watt 750SG halogen quartz light, which retails for $216 and includes 4 permanently attached barndoors. The light is reported to throw light over a 60 degree by 46 degree area for broad, even coverage.
Fluorescent Lighting Options
Fluorescent lighting is commonly found when shooting using found light — this form of illumination is widespread among company offices, stores, supermarkets and other public venues. The major issue with non-professional fluorescent lights is their green cast, correctable with filters at the shooting stage and some additional correction in post-production, and the “flicker” that is the result of the electrical generator that is part of the tube’s power supply. Conversely, this all-in-one package makes a fluorescent light compact to use and able to be supplied by an ordinary AC outlet without any drain on the overall circuits. To avoid this, as possible, choose professional quality fluorescent lights for use in video production.
The lighting advantage of fluorescents is displayed by ARRI’s Studio Cool series; providing a bright even lighting that is well suited for background illumination in studios as well as fulfilling the requirement where green screen use is warranted. There are three models: Studio Cool 4-4 tubes at $1,308.95 retail, Studio Cool 2-2 tubes at $1,423.75 retail and Studio Cool 2+2-4 tubes at $1,437.74 retail.
Another option would be the Videssence Koldlite K110-255BX-D/PM, which retails for $1,000. This fixture offer phase control dimming and wide range of beam angles with 3000K, 3200K and 5500K bulbs available
For a more economical option look to Flolight’s FL-110HM Fluorescent Video Light, which retails for only $200 and features two way barndoors, daylight or tungsten balanced bulbs and a CRI value of more that 90.
LED Lighting Options
LED lights have gained in popularity due to being lightweight and of solid-state construction. There is no filament that glows with heat, instead a light-emitting diode produces light from a piece of solid matter. Less expensive than HMI and tungsten halogen, they are superior to tungsten due to durability. They are color temperature balanced to daylight, eliminating the need for gels, and some can be adjusted to cover a range of color temperature. Downsides include a vulnerability to high temperatures which is why heatsinks and cooling fins are used in construction so as to control this. Still. LEDs will never get as hot as a tungsten or HMI fixture. Also, some LED bulbs do not have a stable color temperature — which is why calibrated LED bulbs should be used for any video work.
A good example of the soft light typical of LED fixtures can be found in the Kino Flo Celeb 200 LED panel. The Celeb 200 is fully dimmable with an adjustable color range of 2700K to 5600K and outputs the tungsten equivalent to more than 750W of light. The light features ultra-quiet and cool operation and comes with a honeycomb louvre and gel frame. It retails for about $2,500.
Kits are also available that will not look all that different from those familiar with working with tungsten lighting: for example, a classic portrait lighting scheme can be attained with the Dracast Interview Kit, which starts at $1,385 and included two LED500 Pro Bi-Color panels and one LED160A on-camera light. All three lights are dimmable from 0-100% intensity and are color temperature adjustable from 3200K to 5600K. The kit includes adjustable light stands and a nylon soft case.
For a more portable solution, look to Litepanels’ Caliber Three Light Kit, which retails for $995. These 2-in LED Fresnels each provide the tungsten equivalent of 150W of light. Besides three daylight balanced lights, accessories include three multi joint tripods, three sets of color balancing gels and a compact light stand.
LED panels can offer some unique advantages over more traditional light fixtures, as is demonstrated by the Westcott Flex LED panel, which retails for $600 and can literally flex into a variety of shapes. The panel comes in both daylight and tungsten balanced varieties.
HMI Lighting Options
HMI (Hydrargyrum Medium-Arc Iodide) is an arc lamp that produces light. While popular for production due to their high quality, their expense is prohibitive to those with modest/limited budgets. An HMI light functions by providing an ignition pulse through electrical ballasts which are separated from the head via a header cable. Arc lamps are many times more efficient than incandescent lights and run cooler using less power. This makes them a popular source of lighting. HMI’s color temperature comes in at around 5600K and so eliminates the need for corrective gels when used in conjunction with natural light.
Due to the voltage requirements, one might think that an HMI kit couldn’t be small — a false assumption as the ARRI Compact 1200 watt HMI Fresnel Kit would prove. Retailing for about $7,000, this is a 1200 watt Fresnel with a 6.9-inch lens and a dimmable ballast with DMX control. There is a 50-foot head to ballast cable and includes a four-leaf barndoor set and filter frame.
Light at the End of the Tunnel
Understanding the technologies that make a particular form of lighting function is as important as knowing the best ways in which to implement its use for a particular lighting scheme. This will aid in choosing the best type of light for the situation in which lighting will be used.
SIDEBAR: Light Modifiers
Light may travel in a straight line as regards physics, but getting light to go where you want it to go and looking the way you want it to look requires devices known as light modifiers or shapers.
For example if you’re shooting outside under a bright sun — meaning a hard lighting situation — then any modifier device must replicate this “look.” Modifier devices cover a wide spectrum but can be safely grouped into two categories: hard and soft.
As to the modifiers themselves, they can consist of many different types of devices, for example umbrellas (reflecting off colors such as gold or silver or white or shooting through them), scrim panels consisting of diffusion materials, beauty lights be they incandescent, electronic flash, etc., grid spots, soft boxes and so much more. The idea is to match the modifier to the light source not just so it will work effectively, but also so that the effect will appear natural in the context of what is being shot.
Modifiers of different types can be used together but as a matter of course, trying out how various modifiers work together and the results they generate should be done long before any actual shooting occurs.
Marshal M. Rosenthal is a technology and consumer electronics freelance writer located on the West Coast.