If you are looking for various soft light arrangements, you are set up with LEDs. But I'm interested in bright, hard light, with consistent daylight color. Where do I turn for those in LED land? I don't want a thousand points and shadows, but a strong consistent parallel light beam. Is there something already here or on the horizon (and that hopefully doesn't cost an arm and a leg)? To put it more simply, which LED can make an HMI like M18 obsolete?
LED Light Options
- Thread starter nyvz
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Moseph
Veteran
I think that's asking a bit much for now. For one thing, I can't imagine how large of a heat sink would be required for an LED that's as bright as an 1800w HMI lamp. Seems like there are options out there capable of replacing much smaller HMI's, but I wouldn't worry about replacing an M18 given how efficient the design already is compared to traditional fresnels, and even PAR's.
I don't think anyone has 1800 watt LED emitters yet, so it might be a few years before something can take on an ARRI M18 HMI light. ( likely won't be cheap either as it's market will be as specialized as the M18 market is )
Norman99
Well-known member
Leds are not really measured as brightness in watts but rather in lumens. An 1800 watt led ? perhaps you mean a led that is equivalent to a 1.8K ( 1800 watt) filament. If that is so, then achieving somewhere in that range would require about 20 power class leds that emit approximately 1600 lumens each. Each led would consume about 25 watts of power totalling 500 watts of power drawn from the source ( in this case a led driver(s) ). Leds are approximately 4 to 5X more efficient than filaments and not the exaggerated specs being thrown around. And I am talking about the most recent offerings out there as components. A led having about 100 limens per watt consumed is a very good thing indeed, but that figure should be at the leds' maximum brightness rating and not at the low dimmed setting where almost any led can surpass that figure. led rated at 350 milliamp current (dimmed) can easily produce a high lumen per watt figure but rarely does one drive the led that low. A single led ( not a plasma ) the size of a pea can indeed produce well over a 1.8 K equivalent as a surface narrow spot brightness, but at the expense of being a narrow, almost useless, beam of light. The 1.8 K HMI is most likely in the 40 degree native beam angle and most likely will often be diffused with some sort of light modifiers for a wider spread or softening effect. At that point, the brightness ( or lumen figure ) NOT WATTS, will diminish to half or more depending on the diffusion thickness or material used. Single die leds of 100 watt consumption are out there, delivering low 60ish lumens per watt for a total of 6000 lumens which equates roughly to a 350 watt filament bulb. Still nowhere close to the 1.8K HMI. Perhaps a photometric spec figure of that 1.8K in LUX figures at a specific distance as well as the all important beam angle should really indicate the true brightness rather that just the wattage power consumed from the electrical outlet.
Mitch Gross
Veteran
I'm still waiting for the day that an efficient lens system can be coupled with an array of LED emitters to create a proper point source light engine that can then be fitted into traditional fixtures. It will mean a fat butt on the back of the lamp and certainly added expense, but in theory one could get it down to something even smaller and more optically efficient than a traditional halogen or metal halide bulb. A Hive plasma bulb is the size of a Tic-Tac and the resulting beam angle efficiency is quite useful. The current crop of LED fresnel fixtures from ARRI, Litepanels, Mole -Richardson, etc., do not quite have the beam angle efficiencies of traditional emitter fixtures because their light sources are still too large.
There are commercial LED lights that are sold with a watt rating ( i.e. 50 watt, 100 watt, 200 watt ), which I've always assumed to be a power consumption rating as apposed to a light output rating.
The 1,800 watt designation was from OldCorpse's mention of the ARRI M18 HMI light, which is the brightest HMI light you can power from a standard 1,800 watt household circuit.
So he's looking for an LED light source that would have the equivalent light output as an ARRI M18 HMI light, which is something that I don't think exists right now in the world of LED light sources, and might not exist for quite a while.