Editor's Note: A sidebar to this article entitled "Testing LED Lighting for Video/Broadcast Applications" is available here. This side bar includes a seven-step process for evaluating LED fixtures for video IMAG, video capture for satellite campuses, webcasting and other broadcast applications.
As the use of Light Emitting Diodes (LED) has grown for theatrical lighting applications, most of the fixtures offered have been PAR and floods with red, green, and blue (RGB) LEDs ganged up for washes of color. Today there are some good white-light LED options available as well, and in the past two years manufacturers have been tackling the goal of producing a profile fixture with an LED light engine. While some refer to profile fixtures as ellipsoidals, they technically aren't since they don't use an elliptical reflector. They use shutters and a lens system for beam control so they are referred to as a profile. There is now a range of profiles with LED light engines from a selection of manufacturers that offer beam control with shutters and the ability to add gobos for pattern projection. Manufacturers also are producing Fresnels powered by LEDs that have spot-to-flood control-and the barndoors can actually shape the beam.
It should be noted that while focusable LED profiles and Fresnels are now available, they may not be ideal for every application and should be considered as an adjunct tool for use with conventional tungsten lighting instruments. Look carefully at your needs and test the lighting unit to be sure it meets the throw distance, brightness, and color rendition that you require. You should also be aware that you cannot measure color temperature in the same way since LEDs are not the same as tungsten lamps. They are not a black body radiator like a tungsten filament, where you can use color temperature-measured in Kelvins-as a reference to the whiteness of light sources. For LEDs, just like with fluorescent or high-intensity discharge lamps, the measurement is a close approximation to the "apparent" color temperature, which is referred to as the Correlated Color Temperature (CCT). Also, as with any new technology, how to handle troubleshooting and maintenance long-term are important questions to ask upfront.
To help church technical staff look at what is on the market that especially applies to their needs, CPM spoke with the following manufacturers:
John Gresch, vice president, lighting products, Arri, www.arri.com or lighting-info@arri.com; Steve Gilbard, president, Illoomitech Distribution, North and South American Distributor for Brother, Brother & Sons, www.illoomitech.com or steve@illoomitech.com; Jerry Mitchell, entertainment LED sales with LED Source, North American distributor for Coemar, www.coemar.com/www.LEDsource.com or sales@ledsource.com; Joe Bokelman, ETC architectural market manager, Matt Armendariz-Kerr, ETC product manager for the Source Four LED, www.etcconnect.com; Frank Kosuda, vice president, DeSisti,www.desistiusa.com or fkosuda@desistiusa.com; Pat Grosswendt, co-founder and chief technical consultant, Litepanels, www.litepanels.com; David Crookham, vice president of sales and marketing, Prism Projection, www.prismprojection.com or dcrookham@prismprojection.com; Fred Lindauer, director of U.S. operations, Robert Juliat, www.robertjuliatamerica.com or info@robertjuliatamerica.com.
CPM: What important considerations do houses of worship need to keep in mind when looking at focusable LED lighting products?
GRESCH: Choose a control console that can utilize the features of the units remotely. Also, we strongly suggest a camera test with any specified lighting gear. Look for consistency of correlated color temperatures among fixtures.
GILBARD: The transition to LED theatrical lighting fixtures is just like moving to any other technology-as the field expanded very rapidly in the past one to two years there have been many products that were not equivalent quality to the fixtures that were the standards of the professional lighting industry. Only now are true theatrical lighting fixtures coming to market that can make the transition one of great advantages without having to accept significant compromises. Look for quality fixtures that meet both needs and the standards.
MITCHELL: I think one of the major considerations when picking this type of fixture is the fact that you do not need to have volunteers up changing lamps or colors, at the risk of getting hurt. Also remember, buying the cheapest fixture on the market is not always the best decision. It is important to have a long-lasting, reliable fixture that can reduce maintenance and energy costs.
KOSUDA: Test the fixtures. Test with your cameras. Consider all options. Also choose companies that are reputable. With the huge infusion of LED fixture manufacturers, I believe that the small companies that are claiming that their fixtures offer 50,000 hours may not all be in existence when those fixtures do fail. LEDs in general are very fragile to operating temperature. Even if the LED fixture manufacturer utilizes a very reputable LED manufacturer, it is important to know if the LED is being run-and more importantly-cooled properly within the unit. If not, the LED will degrade much faster and may fail prematurely.
BOKELMAN: When looking at LED fixtures, it's not efficiency that people should look at, but efficacy (‘efficacy' defined in this case as the light leaving the lens). There is a trend for venues to be very interested in LEDs conceptually, but then in practice they find that the fixtures are often not as bright as expected, not bright enough, and may not actually provide good white light or colored light-for such a large investment. The lumen-to-watt equation is a very important thing to pay attention to.
Armendariz-Kerr: I would encourage people to look at the photometrics when thinking about throw distances. You will notice the distribution of the light is a little different on the LED fixtures. If you are looking at footcandles, per say-since LEDs have a flatter field-it is going to distribute those footcandles out a little more. It is something to keep in mind that it is going to act a little [differently]. Knowing how the light is distributed is important to being satisfied with the results.
GROSSWENDT: Understanding the working differences between new and old technology remains one of the biggest challenges. Legacy fixtures generate so much heat that they had to be a certain distance from the talent for comfort. Newer LED technology throws less heat which means that the lights can come in closer. However, in many houses of worship the need to hide the lights determines their proximity to the talent, and in these cases distance will always be a consideration. For houses of worship where lights are able to work in close proximity to the talent, transitioning to LEDs is a perfect way to save on lighting costs.
CROOKHAM: A key element in choosing LED products is the color consistency and reliability of the LEDs over the product's life. LEDs by nature change with time and temperature. We have worked to address this with real-time automatic color calibration in each instrument.
LINDAUER: I think LED products will become more and more attractive to the HOW market. The disadvantages of higher initial fixture costs will be offset by the advantages of less infrastructure costs (power, distribution, dimmer rack costs, etc.) and maintenance.
CPM: How do manufacturers balance customers' demand for power efficiency with demand for higher-output products?
MITCHELL: Everyone wants to save money, and cutting power consumption is a concern to many. However, design is always key. The end-user needs to first understand three- and four-point lighting systems in order to achieve the desired light levels. Once you prove that the desired light levels can be met, lowering operating and maintenance costs becomes more of an important factor.
KOSUDA: ‘Usable' high output was the main factor when designing the fixtures. It was not the intent to produce a LED fixture that produced the most light. The intent was to produce a fixture that offered the same characteristics of tungsten Fresnels, which includes a smooth focusing field, barndoor control, and single shadow projections. Harsh raw light was not the goal; usable high output was the goal. This is why we chose the LED array technologies in a fixed CCT. Customers need flexible maximum output. They want a fixture that, when on full, generates the highest output with stable color temperature, flicker-free and consistent intensity. They then want the ability to control the beam intensity and focus without having negative color shifts and unreliable output.
GROSSWENDT: LEDs inherently require less power than legacy fixtures, but we focus on other design characteristics like the quality of the LED engine and the thermal dynamics, as well. By using great components and reducing heat output we can keep the quality of the light output high and [ensure] that our fixtures will have a long life, which is paramount for providing a serious ROI for users.
After looking at a number of LED-powered profiles and Fresnels, you-like many others-will see that great strides have been made in this class of lighting fixture. If you are building a new facility, renovating an existing one, or just wanting to upgrade your lighting for your facility, you should feel comfortable knowing that focusable LED fixtures are viable alternatives for many situations. As with any purchase, you should speak with the manufacturers or your theatrical equipment dealer to arrange a demonstration in your facility. Try out a variety of the products; compare them to your existing lights and judge for yourself if they truly are a replacement for your existing lighting.
CPM would also love to hear your feedback on this article and your take on LED profiles and Fresnels. If you're currently designing with these units, let us hear about your experiences at editorial@churchproduction.com.
