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Old November 2nd, 2012, 03:16 PM   #1
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LED MR16 Replacement

Has anyone found an LED version of an MR16 bulb that is a solid replacement for halogen? Bright & good CRI, to replace a 35 to 50W MR16?

I have an Anton-Bauer Ultralight 2. Have gone to lighting supply places and tested some LEDs and they do work, but haven't found anything yet that properly replaces the regular MR16s. Looked at them online but at around $20 a pop, not eager to buy a bunch just to test them.
So hoping someone has found a solution. I would rather stay with the Ultralight 2 than get an LED camera-mounted light. (Using an EX1R)

Thanks.
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Old November 2nd, 2012, 11:35 PM   #2
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Re: LED MR16 Replacement

A halogen 50W for example at the average beam angle of around 40 degrees ( without the flipdown diffuser) is approximately 900 lux measured at the proverbial 3ft. distance. You would need a MR16 LED equivalent in the order of a 10 watt emitter with an efficacity of 90 lumens per watt output to be able to muster that kind of brightness. the only led, in my opinion that can actually better that is the CREE MTG-2 emitter that really consists of a 12 die cluster within that single chip. The trick is to find a compatable led driver so that it will feed a DC current to the led with a DC driver input that is within the range of your DC power source ( 12 to 14.4V). Not easy to find, especially when you consider the form factor of either the M16 bulb itself or the small internal confines of the Ultralight. Most MR-16 led units are not suitable for video use as their CRI and color cast are not that great and more important is that the driver that is built within the MR-16 bulb is most likely the PWM type that may cause banding artifacts at certain camera shutter speeds. I have gutted out an ultralight that was discarded in the trash as an experiment with a led ( the MTG 4000K color temperature) and have installed a 2.8 amp DC driver along with a dimming function. Took many hours of trial and error, especially mating a reflector with the MTG that will give a nice wide 70 degree beam. The unit worked perfectly but the cost was over $80 in parts not counting over 2 days labor in drilling, fitting and grinding. The resultant output was 1400 lux (75 watt equivalent) and drawing a paltry 15 watts from the battery. Not bad at all. The reason MR-16 do not offer the high brightness is that their small form factor does not permit the led to have adequate heat sinking required to go over the 7 watt threshold of power consumption which severely limits the brightness to around a 35 watt bulb, at lest that is the case for now. You may also notice that color temperatures of 3200K in leds do have a significantly lower brightness (lux) than their cooler counterparts. If you just want to replace the 35 watt filament MR-16 you may find a few choices available in leds, the 50 watt may be almost impossible at hi CRI.
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Old November 4th, 2012, 10:56 PM   #3
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Re: LED MR16 Replacement

http://www.cree.com/~/media/Files/Cr...G_MR16_Ref.pdf

This is what i attempted to do ( see photos at bottom) but came up with using a different led driver that was capable of 2.8 amps which allowed the led to equal the 100W halogen brightness. The unit gets very hot at full brightness and necessitated a finned copper heat sink.The Cree MTG led is presently available in hi 90CRI but at 3000K designated as MTG-2. My configuration cannot be inside the small form factor of the MR-16 due to thermal management issues and don't think will be commercially available because of that. The most the MR-16 may do with the MTG is perhaps 12watts power draw at the led and 16 watts total draw including the driver for a 50W halo equivalent.On paper it is feasable but I have not seen any on dealer's shelves yet.
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Old November 5th, 2012, 01:17 AM   #4
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Re: LED MR16 Replacement

Hi Arthur thanks for the excellent replies. That document is very interesting, there is obviously a tremendous amount of engineering behind the effort to replace the standard MR16. The Cree MTG/MTG2 looks really good. I am looking at the bulbs I've been using in my Ultralight Ushio Model BAB 20W with 36 degree beam angle. I tried to keep the wattage down to preserve battery life. So a 35W equivalent LED would probably be just fine especially as I use the mini softbox on the UL2.

I looked up the average output of a 20W Halogen MR16 (flood/38) , and it's around 250 Lumens. See the link below for a 7W LED MR16 below that uses the Cree LED element you mentioned. Couldn't find any others. Here are the specs on it:

Energy Consumption: 7W
Lumen Output: Warm White - Up To 510 Lm / Neutral White - Up To 550 Lm
Up to 78 Lumens Per Watt
Input Voltage 12V AC/DC
CREE MT-G Chips rated to 50,000 hours
orlight.com

So it should give double the output of a 20W halogen MR16 with the same 38 or 40 degree flood beam angle. Found one for sale in the UK for about $45.00 USD (compared to about $9 for a 20W halogen).
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Old November 5th, 2012, 08:43 AM   #5
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Re: LED MR16 Replacement

Using the mini softbox will cut that 510 lumens in half or more depending on the transmittance/opacity factor of the material used. The resultant equivalent may be a 15 watt halo equiv.
The native beam angle of the led mr-16 may at 36 degrees may be too harsh on the eyes of the subject that is close for interviews and that will work fine with the softbox but anything over 10 feet distance may not be lit well enough. Also the MT-G version in that unit is the previous one. The newer one has 20% more lumen output at the same power draw than the older one and a higher CRI at that. CRI numbers really are not a good indicator of color quality rendition as I have used in my previous lamp designs the Cree XM-L which in my opinion at CRI 85 was a much better performer. One must do comparative tests side by side with real subjects to determine which led is best. There are so many different leds out there but even at that most of them fall in the same category of being of bluish nature obviously for higher lumen figures at the high 6000+
kelvin for the most light possible. What most fail to see is that a yellow or amber filter must be used to correct for indoors which will set you back a full stop or more thereby negating the benefits of that high advertised lumen figures that are more than likely inflated.Add to that a diffuser to widen up that narrow beam and now that nice high lumen figure just went down to 1/3 of it's advertised value. I have never taken any advertised photometric data seriously, especially when they do not mention the distance AND beam angle measured but compare it with a bulb equivalent. An example would be like : 256 led light with 256 tiny leds equivalent to a 200 watt halogen consuming just 20 watts. A bell should ring here ??.
I have a small keychain flashlight that throws a very narrow bluish beam of 4 degrees and when I measured that with my light meter at 3 feet gave me an equivalent of a 400 watt ( 7,000 lux) halogen. If you want a chart to figure out lux/F stop/ASA equivalents here's a good one: Conversion Tables for LUX to EV and EV Exposure Tables for Infrared Photography. 999WED.com.
The case with my flashlight just goes to show that beam angle and distance are crucial to see the true brightness picture. If I happen to widen that flashlight beam either by a diffuser or reflector/optic, then that pin spot brightness would diminish to nothing useful for video capture. That is another reason most led lights out there have that native narrowish beam. Them teenie weenie led clusters all have the clear hemispherical cap on them for a reason. That cap is really a lens that narrows down the beam of each led considerably for an apparent higher lux/lumen/brightness value.
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