Augustin-Jean’s inspiration came from trying to reduce the weight of a large spherical lens by carving concentric rings — like the rings of a tree — in a flat lens. Each ring bends the light slightly more than the one beneath it, so the light rays all project as a beam. Outside of lighthouses and movie sets, Fresnel lenses are also used in car headlights and those large, outdoor event lights they shine into the night sky at movie premiers, similar to the one Commissioner Gordon uses to summon Batman.
Fresnel lights used on film sets are fairly simple tools, quick to master. They are a light source of varying size and intensity and have the ability to be used as a spotlight or a flood light. The apparatus itself is a lamp of various wattage that sits on a movable track behind a Fresnel lens and in front of a spherical reflector. The reflector directs most of the light towards the Fresnel lens, which then corals the illumination into a beam. All of this is encased in housing made to dissipate the enormous amount of heat the unit produces. There is a knob, usually in the rear of the housing, which is used to move the lamp/reflector team along a track, allowing the beam to be spotted or flooded. There are usually four brackets on the front of the light — three fixed and one moveable — to hold barn doors, speed rings, scrims, and other tools. Finally, there is an AC power jack to provide electricity and a standard ?-inch (16 mm) stand mount and yoke to mount the light to a light stand or ceiling pipe grid. Simple, right? Trust me, they are even easier to use than I just explained.
FRESNEL LIGHTS USED ON FILM SETS ARE FAIRLY SIMPLE TOOLS, QUICK TO MASTER.
There are many accessories that can be added to Fresnels to further control their light. These are traditionally sold separately, though some may be included with the new LED Fresnels, depending on the make and model. A four-leaf barn door can be mounted to the front brackets of the light to control the beam. Round scrims — metal screens mounted in a metal frame — can be placed in front of a light into these same brackets to reduce light intensity. A speed ring that can hold a soft box can also be added to these same brackets to create a soft, wrap-around light. Traditional tungsten Fresnels don’t come with built-in dimmers, but external dimming systems can be bought for about $50. Blackwrap(TM) or CineFoil(TM), essentially heavy, black aluminum foil, can be used to shape light. Gels and diffusion elements can be attached — usually to the barn doors using C47s (a.k.a. wooden clothespins) — to change the color or intensity of the light.
If you’ve ever taken a film lighting class, you should be aware of a typical three-point lighting system. Often used for interviews, three or four Fresnels act as a key light, a fill light, a rim/hair/ back light, and the fourth as an optional background light. You’ve most likely seen the results of thousands of these set-ups in just about any documentary with a sit down interview or in long-form news television shows, such as 60 Minutes. Fresnels are also great for product shots where you need to light relatively small, immobile props from a distance. And as mentioned earlier, many film stages will have a ceiling pipe grid filled with hanging Fresnels as well as other lights, usually controlled from a light board.
A note about the tungsten lamp, that little glass & ceramic unit at the center of the Fresnel: I overheard someone on set in the electrical department telling a production assistant that a “bulb” is something a gardener puts in the ground during springtime, from which a flower grows; a “lamp” is what we use on a film set — another tip to save you from being labeled newb on your first day as a production assistant. NEVER touch this glass lamp, whether it’s cool or hot. When it’s cool, your finger will leave a small, invisible amount of oil on the glass surface which will most likely heat up once turned on and cause the lamp to explode. Those little things aren’t cheap and a real inconvenience if you don’t have an extra on set. When hot, they can give you a truly nasty burn. Apparently 70 percent of the energy used by a tungsten light is dispersed as heat, with only 30 percent visible as light. Use gloves when handling lights after they’ve been turned on.
Most Directors of Photography seem to prefer the color of tungsten Fresnel lights to newer LED lights, as well as the control the traditional lights allow. These lights do require a relatively large amount of electricity and get extremely hot.
Although the color produced by LED Fresnels, especially early models, is less desirable by many, they do draw much less power, stay cooler and can have the ability to be dimmable and/or switch between daylight and tungsten in color from within their single unit. I’ve also read that more powerful LED Fresnels can produce fan noise.
Fresnels are known for their directional light that can produce hard, crisp shadows. Do an image search for George Hurrell on the Internet and you’ll see examples from this 1930’s commercial movie-star portrait artist who loved using Fresnels. These workhorses of the lighting world can be found on sets and on location across the world, making the movies, television, and news shows we watch daily.
Mole Richardson is responsible for the nicknames of these different sized Fresnel lights. These nicknames are widely used on sets, a least in the USA.
100-watt Fresnel light is called an “inky.”
200-watt Fresnel is a “midget.”
650-watt Fresnel is a “tweenie.”
1k-watt Fresnel is a “baby.”
2k-watt Fresnel is a “junior.”
5k-watt Fresnel is a “Senior.”
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