# Robert Juliat LED Profile Spotlight



## Les (Nov 7, 2009)

Found this on the Barbizon Lighting Blog


[media]http://www.youtube.com/watch?v=Pra__dMaBK4&feature=player_embedded[/media]

[media]http://www.youtube.com/watch?v=M0Cz8a0K-9c&feature=player_embedded[/media]


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## starksk (Nov 8, 2009)

Looks interesting. Hard to tell if the stepping in the dimming is from the fixture or the camera's iris trying to adjust to the changes in light levels.


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## PeteEngel (Nov 8, 2009)

The stepping you see is from the camera auto iris. this fixture dims without stepping.


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## derekleffew (Nov 8, 2009)

Hey, does tristanpants know about this?


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## Kelite (Nov 10, 2009)

derekleffew said:


> Hey, does tristanpants know about this?



I'm guessing yes, since he has been active on the LN while this RJ unit has been discussed. Whether or not it matters to him, dunno...


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## Footer (Nov 10, 2009)

I have a feeling this is going to be the theme to LDI this year. I know we are all thinking it... but ETC just bought a large LED company... If they make an LED unit its going to essentially bring this race to an end. If you can just switch out the basecap of your fixture with an LED and somehow they get it to run on a sensor dimmer... its over.


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## PeteEngel (Nov 10, 2009)

i would think that the way LED's emit light that an ERS would be less efficient at collecting light and less precise at projecting any gobos, also why would anyone need a dimmer to control an LED Fixture....simple relay power and dmx control and you're off. i would think that alone saves lots of money on any installation...but i have to admit, i'm a bit biased...


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## JD (Nov 10, 2009)

Unless the LED assembly ignores the current reflector and has its own built in. Then it could be a direct plug in. The second part (dimming) may be tricky. High power LEDs usually have an active drive circuit, and work at a much lower voltage. At least, you would need an external electronics pack. Still, conventional dimmers would not work. 

I would not put it past ETC to come up with a "trick" mode of operating their dimmers for their LED fixtures. The whole thing could then roll out like dimmer doubling in that you would program the dimmer for LED mode, then have a cord wart in line with the fixture. We shall see 

EDIT: Actually, just thinking that idea through and it would be easy. The "trick out" would be to prorate the dimmer so that it outputs 50 to 100% as the channel fader goes from 0 to 100%. This would provide full time power to the electronics pack next to the light. The pack could then reinterpret the switch-point and provide the appropriate drive to the LED for a 0 to 100% sweep. The whole layout would be workable without any rewiring and could be mixed with non-LED fixtures on other channels. Just thinking out loud...


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## Footer (Nov 10, 2009)

JD said:


> Unless the LED assembly ignores the current reflector and has its own built in. Then it could be a direct plug in. The second part (dimming) may be tricky. High power LEDs usually have an active drive circuit, and work at a much lower voltage. At least, you would need an external electronics pack. Still, conventional dimmers would not work.
> 
> I would not put it past ETC to come up with a "trick" mode of operating their dimmers for their LED fixtures. The whole thing could then roll out like dimmer doubling in that you would program the dimmer for LED mode, then have a cord wart in line with the fixture. We shall see
> 
> EDIT: Actually, just thinking that idea through and it would be easy. The "trick out" would be to prorate the dimmer so that it outputs 50 to 100% as the channel fader goes from 0 to 100%. This would provide full time power to the electronics pack next to the light. The pack could then reinterpret the switch-point and provide the appropriate drive to the LED for a 0 to 100% sweep. The whole layout would be workable without any rewiring and could be mixed with non-LED fixtures on other channels. Just thinking out loud...



To me, thats the real trick... making it work in conventional systems without running DMX all over the place. It would be a nice option if it was self contained, but I know many theatres would replace their entire stock if you could just plug them it. If you would have to go throw some settings in the CEM, that would be workable.


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## MNicolai (Nov 10, 2009)

You guys are starting to jump the gun on ETC's upcoming product release. I don't think it will be an LED replacement cap, for two reasons.

1) They said they're revealing an entirely new product _line._ That implies more than just a single product.

2) ETC is historically known for waiting until other companies get a solid grip on new technologies, then they toss in some innovations and release their new products, but only after they've watched other companies make their own mistakes first.

I agree with Footer; I think LED's will be a big thing this year at LDI, and maybe even the Lifi plasma light sources, but I don't expect that ETC is quite ready to hop onto the LED ERS boat, at least not via a replacement cap for the existing Source Four product line. Also, I do recall hearing Fred say he wanted to do more with the Revolution to spice things up, so maybe they'll be adding some ML's or fixtures designed around the concept of LED's instead retrofitting incandescent sources.

I would certainly not mind seeing a shootout between a 575w S4 and this Robert Juliat fixture, with focus on the the grounds of intensity, evenness of the beam spread, and color temp. Also, any word on color mixing? I don't have my fingers crossed because I know it's hard enough to manipulate an LED into acting like a point source, much less getting an array of them to change colors.


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## JD (Nov 11, 2009)

The problems I foresee is the nature of "white" LEDs. There actually is no such thing! LEDs are monochromatic in nature. White LEDs work by using a UV LED with phosphorous to convert the UV to visible lights. As such, the spectrum has the same problems as a CFL bulb. In other words, standard gels are going to produce some unexpected results. It will be interesting to see how this progresses.


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## Dalamar (Nov 11, 2009)

I don't usually mettle in other people's discussions as an uninformed (and uninvited) guest, however...


MNicolai said:


> ...but I don't expect that ETC is quite ready to hop onto the LED ERS boat...


 
The Juliat fixure is a *profile *(condenser lens + aspherical PC lenses), not an ERS. It's not an Ellipsoidal fixutre (like a S4) and that is precisely why it can get the job done with LEDs.


MNicolai said:


> I would certainly not mind seeing a shootout between a 575w S4 and this Robert Juliat fixture, with focus on the the grounds of intensity, evenness of the beam spread, and color temp. Also, any word on color mixing? I don't have my fingers crossed because I know it's hard enough to manipulate an LED into acting like a point source, much less getting an array of them to change colors.


 
No color mixing just yet. Let's start by getting a stable, reliable source and we'll go from there. It's pretty neat, the optics render images with dead-on precision and the source is utterly flat. Just like any profile fixture today, it kicks any ERS in unsportsmanlike parts.


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## PeteEngel (Nov 11, 2009)

Well said Thierry, and might i add that this unit has 60% of the output of the RJ 1k Tungsten profile, a beautiful field of light, and will be available in different color temps. and will fit into existing 600sx profiles.


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## derekleffew (Nov 11, 2009)

Dalamar said:


> I don't usually mettle in other people's discussions as an uninformed (and uninvited) guest, however...


But that is the essence of ControlBooth: "To provide a venue for discussion, information exchange, and technical advice, related to technical theatre, in a casual and fun atmosphere that fosters friendships among its membership."


Dalamar said:


> ...The Juliat fixure is a *profile *(condenser lens + aspherical PC lenses), not an ERS. It's not an Ellipsoidal fixutre (like a S4) and that is precisely why it can get the job done with LEDs. ...


So what is the shape of the reflector in the RJ LED Profile? I think we're splitting hairs here. US practice has the terms ERS and profile being synonymous, as the quality of the output is similar, both use framing shutters/iris, and can project a gobo. The MAC2000 Profile uses an ellipsoidal reflector, but one wouldn't call it an ERS; likewise with a Super Trouper.


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## PeteEngel (Nov 11, 2009)

the RJ profile uses an aspheric lens for light collection, the reflector isn't the primary collector, like in an ers. there is a small spherical reflector used to collect light from the back of the lamp. as for an RJ profile and any ers being equivalent in nature in regards to pool of light and gobo projection, well that just isn't the case. i think the closest one could say is that an ers does have a pool of light and can project gobos...  but like i said before, i'm a bit biased. i'm new to CB and haven't set up a signature for my posts. 

pete
Robert Juliat USA


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## MNicolai (Nov 11, 2009)

PeteEngel said:


> the RJ profile uses an aspheric lens for light collection, the reflector isn't the primary collector, like in an ers. there is a small spherical reflector used to collect light from the back of the lamp. as for an RJ profile and any ers being equivalent in nature in regards to pool of light and gobo projection, well that just isn't the case. i think the closest one could say is that an ers does have a pool of light and can project gobos...  but like i said before, i'm a bit biased. i'm new to CB and haven't set up a signature for my posts.
> 
> pete
> Robert Juliat USA



Welcome to CB, Pete! It's always nice to have manufacturers' reps here to discuss products with.

Do you know if there are any exploded assembly views of this fixture available that we could use to get a better idea of the inner workings of it?


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## PeteEngel (Nov 11, 2009)

At the moment there is only the diagrams of the standard 600sx profile...
http://robertjuliat.eu/Documents/DN40635500_n_600sx.pdf
this is available on the RJ website. it gives you an idea of the internals of the lamphouse as well as the zoom lens tube. you can figure out where the LED module would have to go after viewing the YouTube video. As for the LED module, there is nothing available yet.


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## Dalamar (Nov 12, 2009)

derekleffew said:


> So what is the shape of the reflector in the RJ LED Profile? I think we're splitting hairs here. US practice has the terms ERS and profile being synonymous, as the quality of the output is similar, both use framing shutters/iris, and can project a gobo. The MAC2000 Profile uses an ellipsoidal reflector, but one wouldn't call it an ERS; likewise with a Super Trouper.


 
Well, as I said, I’m no expert, but, if I may… 

An ERS (Ellipsoidal Reflector Spotlight) is, by its very definition, using… *drum roll* … an ellipsoidal reflector. Now, ellipses have, again, by mathematical definition, 2 separate focal points. 

Notwithstanding that many of us are not physicists and taking for granted that, in a perfect physical environment, and in Layman’s terms:

a) Everything that happens on one side of a mirror is also true and happens on the other side.
b) Any photon coming from a light source set at one focal point and hitting the surface of the ellipsoidal mirror will invariably go through the second focal point. 

Note that there are a few conditions which need to be respected for this phenomenon to be true, two of which being:


a) the source must be as compact as possible and
b) the source must be dead on the focal point. 


On the other hand, profile fixtures tend to use a condenser lens set (collecting a significant amount of light) and a secondary lens (commonly bi-convex) which create the secondary focal point. The (typically) spherical reflector enhances the light output but does not otherwise contribute to shaping the image, as does the ellipsoidal. So, in this case, the LED source is not reflector dependant, like standard sources are. 

Now, I’m insisting on that secondary focal point because that’s what’s required to project an image, or, in other words, make a spot focusable to a point where you can have sensible definition, i.e., gobos.

While the ERS is the naturally preferred North-American choice when it comes to focusing theatrical fixtures, most profile fixtures will end up producing a far better, flatter result, if somewhat less powerful than the former. The condenser lens is imaging the entire LED face, therefore the less efficient optical system for standard lamps becomes the most efficient (theoretically) for the LED system, all the while maintaining it's optical and projection superiority. Since the Profile fixture does not necessarily require a smaller source precisely set at the primary focal point, that technology is, by very definition, the one of choice to have come up with focusable LEDs first.

If the (expected) results are anywhere near what’s promised (60% of a standard 1kW profile output), Robert Juliat will have the only fixture in the world that can be effectively used with 4 types of light sources (Tungsten, MSR, CMD and LED). 

Both the Ford F-150 and the Audi A8 have 4 wheels and a steering wheel (and a few other insignificant parts..) and yet, there’s a world of differences between the two. Here, despite both being able to use shutters, we are but a deep chasm away from an ERS and a Profile being similar. Perhaps, as you put it, without splitting hair, we should revise our "common knowledge" towards rightful definitions =)


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## derekleffew (Nov 12, 2009)

Dalamar said:


> ...Now, ellipses have, again, by mathematical definition, 2 separate focal points. ...
> we should revise our "common knowledge" towards rightful definitions =)


To further whip the deceased equine: Lenses have focal points. An ellipse has two foci.


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## JD (Nov 12, 2009)

Generally, the more glass, the dimmer the light. The Hubble telescope, which works like a beam projector in reverse, collects all of it's light on its surface reflective (improperly ground) mirror. Unfortunately for the Hubble, this advantage was lost a bit when it had to be fitted with glasses.  Anyway, in the ERS, the reflector is indeed responsible for the first focal (err.. foci) point. No lenses means no light lost due to secondary reflections. I am somewhat mystified regarding the LED light source, as most LEDs actually used the cup the junction is mounted in as a primary internal reflector. In this case, due to the phosphorous coating, not so much a reflector as a target that converts the primary UV into white light. Due to the nature of the light coming off of the target, I would expect the beam to be quite wide and incoherent. (Monochromatic LEDs do not have this problem as the do use the cup as a reflector and therefore the beam has better control.) I would think the goal would be to use as little glass as possible to bring the output under control, considering that LEDs still have an output disadvantage over standard sources. I am really fascinated and deeply curious to see how these problems are handled.


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## PeteEngel (Nov 13, 2009)

JD, quite right on the more glass, the less light, though the percentages are minimized for a number of reasons...as a laser guy once described, you lose 2% of light per plane of glass...that being said, unless you have first surface reflectivity on a mirror, that means that you lose up to 8% of light from a glass mirror with a backside coating...no biggie, the important aspect would be that light is both a particle and a wave, and as a particle it bounces off an elliptica reflector at whatever angle and enters the gate (second foci?) at a different angle from all other light particles...not great for imaging. as a wave, the light wave hits the reflector at an angle and does chormatically refract. and the bigger the angle on the reflector, the greater the refraction...and all before getting to the gate (foci). the condenser optics take the light from less severe angles, and send it through the gate at the (basically) same angle, much better for imaging. with a standard lamp source, there is obvious light not used but what is used is much more coherent and of generally greater quality. 
as for the LED aspect...you are both correct and incorrect, but that will have to wait until after LDI...


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## Dalamar (Nov 13, 2009)

derekleffew said:


> To further whip the deceased equine: Lenses have focal points. An ellipse has two foci.


 
How so very true. I stand corrected. =)


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## derekleffew (Nov 13, 2009)

"Foci" is the plural of "focus."

There are many methods to produce a crisp image, but heretofore with an incandescent light source, the most efficient (but not necessarily sharpest), was the ellipsoidal reflector. The (in)famous Parellipsphere not withstanding, likewise the lens-less Berkey-Colortran ColorSpot followspot. This discussion caused me to search for the Uni-par "PAR Squared" fixture (using two parabolic reflectors) that caused a minor fuss at least year's LDI, but I can't find any mention of it on Unipar's site. Does anyone know what happened to that?

It sounds like RJ (and others) are investigating new ways of delivering light to the gate and not trying to put an LED source at the first focus of an ellipsoidal reflector. However it's achieved, the industry will be theirs if it performs comparably to a SourceFour Profile [] with an HPL750/115 lamp, and is reasonably priced.


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## JD (Nov 13, 2009)

The Colortran !! Sometimes known as a water barrel with legs


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## Dalamar (Nov 17, 2009)

derekleffew said:


> "Foci" is the plural of "focus."
> 
> There are many methods to produce a crisp image, but heretofore with an incandescent light source, the most efficient (but not necessarily sharpest), was the ellipsoidal reflector. The (in)famous Parellipshere not withstanding, likewise the lens-less Berkey-Colortran ColorSpot followspot. This discussion caused me to search for the Uni-par "PAR Squared" fixture (using two parabolic reflectors) that caused a minor fuss at least year's LDI, but I can't find any mention of it on Unipar's site. Does anyone know what happened to that?
> 
> It sounds like RJ (and others) are investigating new ways of delivering light to the gate and not trying to put an LED source at the first focus of an ellipsoidal reflector. However it's achieved, the industry will be theirs if it performs comparably to a SourceFour Profile [] with an HPL750/115 lamp, and is reasonably priced.


 
Humbly, in my experience, if you're expecting a S4, or any other spot you have in mind, you're asking for nothing but disappointment. Even if we need to compare for reference, my suggestion would be that anyone coming to check that thing out comes with an open mind. The only expectation one should have is to see something different. 


And I know how hard it is...


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## Dalamar (Nov 18, 2009)

Well, I got to play with that baby this morning. 

Very, very nice. I can very much see the day when we'll work in dimmerless theatres...

If some of you come to LDI, stop by RJ's booth and ask Fred Lindauer for a demo: it's worth your time, I assure you. 

Well done, Juliat!


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## dvsDave (Nov 21, 2009)

I've got a demo scheduled with them in the morning. Who knows if they will let us capture any pics or shoot video of it, probably not, but we are going to try!


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## dvsDave (Nov 25, 2009)

Well, we got no footage, but it's a pretty amazing fixture. It's still a prototype, so specs may change, but there are a few things I will say. I was impressed by:

Ease of retrofit/installation
options for different color temps
double shutters
shutter lock
Gobo's had a noticeable blue fringe around the edges, diochrioc glass looked amazing. 

The rest gets into technical details that may/should be obsolete by the time this is officially announced. For instance, the brightness compared to an S4 may change before it ships, so I won't comment on that. Please do not bombard me with more questions, this as much as I'm willing to reveal at this time.


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## Les (Nov 25, 2009)

It definitely sounds like a step in the right direction!


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## SteveB (Nov 25, 2009)

If it doesn't change color via the LED system, what's the point.

LED's have their uses, but image projecting spotlights justs seems like a poor use of the light source. 

And FWIW, double sets of shutters was done 50 years ago with Patt ellipsoidals in the UK and NOBODY has bothererd since then, so possibly that's a feature set that isn't much called for given the add'l price and trade-off's. 

SB


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## wfor (Nov 25, 2009)

Footer said:


> I have a feeling this is going to be the theme to LDI this year. I know we are all thinking it... but ETC just bought a large LED company... If they make an LED unit its going to essentially bring this race to an end. If you can just switch out the basecap of your fixture with an LED and somehow they get it to run on a sensor dimmer... its over.



Ok so this is WAY out there, but what if there was a way of having a standard dimmer circuit control an electronics pack that was the replacement to a standard lamp socket assembly? Like say, you set the dimmer at 75% and the electronics can "read" that. Essentially it would be a glorified socket tester... Then the lamp would be powered by a secondary power supply. I know, about as inconvenient as running DMX all over the place, but at least it could be one circuit for multiple fixtures. 

I know this is way the heck out there, and really not very efficient... but its a stab.


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## tjrobb (Nov 29, 2009)

wfor- IIRC this is essentially how two-wire fluorescent dimmers work. I know the Mark X from Advance senses the RMS voltage and adjusts the output of the lamp(s) accordingly. In theory the same concept could work for LED sources as well.


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## Dalamar (Dec 1, 2009)

Just a THOUGHT here, *wfor*: Aren't LED actually eliminating dimmers altogether? Why would we even bother with this costly, obsolete equipment with LED sources?

Also, *SteveB*, the point was NOT to make a RGB fixture. I think it's fair to say that the challenge here was to actually be able to produce an image we're used to control with conventional fixtures. Furthermore, may I remind you that the product into which the source was implemented exists in today's market and is in use all over the world; it's not like RJ had to go back 50 years to come up with something that they already massively produce. It would be wrong to say "for the additional price" since it's already a feature of the 600 series. 

It's the best step into the direction of what we'll probably all be working with in a very near and foreseeable future. If I may, I would suggest a more positive approach, as this is the begining of a brand new adventure into lighting technology, one that's literally unfolding before our eyes.


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## Jawbone (Nov 18, 2010)

I believe the power of the LED ellipsoidal will become apparent in its power efficiency, dimming, strobing, color without a scroller, and since its fairly new institute ACN protocol into it's structure with a cat6 input as well as standard DMX for current technology. I use some 120 pcs 3w led pars RGBAW and am still awed by their brightness, color capability and electrical load.


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## Pie4Weebl (Nov 18, 2010)

Dalamar said:


> Just a THOUGHT here, *wfor*: Aren't LED actually eliminating dimmers altogether? Why would we even bother with this costly, obsolete equipment with LED sources?


The reason so many people like the idea of still powering the system by dimmer is that it requires no new infrastructure. From the sounds of it people love the idea of just swapping out the end caps on the S4's and that being all required to update their system to LED.


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