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It is, I think, uncontroversial to consider the VL3000 spot fixture as having a special place of prestige among intelligent fixtures. In that 1200-watt fixture Vari-Lite realized a truly excellent light, one that set the standard for the quality of its brightness, effects and optics, and it has been used extensively in entertainment lighting since its inception. It was, to understate things, a very usable intelligent light.
But LED technology marches ever onward to challenge the dominance of arc-lamp based luminaries, with no sign of retreat. Once a storied dream, today's high-efficiency LED spots rival even the brightest arc-based lights, and the latest offering from Philips Vari-Lite, the VLZ Spot, is no exception.
* Light Source, Cooling and Dimming
The source for this light is a closed-box 620-watt LED engine from Appotronics, with a native color temperature of 8,000 Kelvin. The optics knock this down to a CCT of 7,640 Kelvin at the final output, and there's a linear CTO that smoothly adjusts this down to 3,200 Kelvin. I measured 8,590 lux at five meters at 50 percent zoom after letting the fixture warm up at full power for 20 minutes.
As with most LED-based spot fixtures that I've reviewed, a significant amount of the fixture's physical space is devoted to cooling. LED performance degrades as temperature increases, so it's critical to keep your dies cool. Accordingly, there's a large heat sink and copper heat pipes that surround the LED module at the rear of the light. These performed admirably, and I measured a thermal output drop of only 2 percent (which fluctuated up or down slightly), down from an initial value of 8,760 lux. This is an impressive number; clearly a lot of thought went into the thermal management. Vari-Lite tells me they haven't had to replace an LED engine yet, but told me that, for the sake of fixture longevity, the engine is designed to be easily swapped.
The dimming in this light is completely electronic; no mechanical dimmer is present. The dimming curve very closely matches an ideal square law curve (see graphic), and...