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Steve Haynie

Stage Lighting

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For decades stage lights were high wattage bulbs with colored gels in front of them.  In the last 20 years there have been colored LED lights used on concert stages. 

A friend has noticed the same thing that I have.  When a club has LED lights it makes it harder to get good photos.  At the last show I attended someone else was bringing up the same thing in conversation.  Someone I know who does paintings and illustrations has said that LED lighting does not emit light the same way as an incandescent bulb.  One explanation was that LEDs are constantly flashing while a filament is consistent.  If that is true, then photos under LED lights would occasionally appear dark. 

Can anyone explain what is going on with LED stage lighting that makes it harder to get good photos? 

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Posted (edited)

The simple answer is they're just not bright enough.

Unless you get into real pro-level lighting, the LED fixtures found in most club-level installs (American DJ, Chauvet, etc.) simply don't emit enough lumens. It takes a LOT of energy to create bright white light, and most of those just aren't up to the task.

Traditional incandescent lamps operate on AC power and are constantly turning off and on at a rate of 60 times per second (60 Hz) in the US; 50 Hz in the UK and some other countries. Line power is a sine wave, so if you could see it in slow motion the light would actually be fading in and out 60 times a second. This is invisible to the naked eye, of course, but can wreak havoc with film or video equipment running at 30 frames per second. Remember the old lighting rigs in the 70s? Banks of PAR 64 fixtures (500 or 1000 watts each), creating enough heat to roast a turkey and pulling enough current to power a small city. Heavy, inefficient and power-hungry.

However, a lot of theaters and other fixed-install applications still prefer incandescents - although ellipsoidals or Fresnel as opposed to PARs - because of the "warm" look created by lower color temperatures. The color skews more red/orange instead of the typical blue-white emitted by gas-discharge lamps. Plus, they're quiet - no fans or electronic ballasts make noise.

Enter the gas-discharge lamp. Instead of a filament, light is created by exciting a combination of chemicals in a sealed enclosure between a cathode and anode. Similar to a fluorescent tube, but operating on a much higher level and generally not at 60 Hz - more like a 400 Hz square wave. This makes for a much more efficient light source. Before LEDs took over, this was the standard of the industry in pro lighting. Every rig had 575-watt wash lights, and some combination of 700-watt movers (moving yoke or moving mirror). Bigger stage? No problem. 1200 watts, 2000 watts...at 2500 watts you could shine a hard-edge image on the freakin' clouds at night. The drawback, of course, was it took a considerable amount of energy to strike (start) the lamp, so electronic ballasts (power supplies) had to be invented. And they could get pretty hot, so cooling systems - either fans or even a liquid cooling system - had to be included. But because of the efficiency of switching power supplies, gas-discharge-based fixtures didn't draw anywhere near the line current as incandescents (aka "conventionals").

Then LED-based fixtures came along.

LEDs operate on DC power ("always on") and the brightness can be controlled one of two ways: by reducing the voltage to the LED element or by chopping it up into a pulse-width-modulated (PWM) square wave. However, most of the fixtures found in clubs and small venues are running at full brightness all the time, so the LEDs are running "steady on" all the time.

But you're never going to get pro-level light without pro-level money, and most clubs and bars aren't willing to invest that much.

LEDs have come a long way in the last decade and continue to get better, more efficient and brighter. All but the most old-school theaters have gone LED. Consumer-level stuff has gotten brighter but still has a long way to go in the cost vs. brightness department.

 

I went to a show in a small club last week an the lighting was horrible. Four cheapie fixtures hung from the ceiling in front of the stage and the throw was so dim and short it was almost like no lighting at all.

Anyway, I hope this helps.

And yes, I work for a lighting company.

 

Edited to add: I forgot to mention, another problem with getting white light out of low-cost LED-based fixtures is many of them don’t actually have any white LEDs - just equal numbers of red, green and blue LEDs.
Theoretically, when you combine red, green and blue (RGB) light in equal amounts you get white. But because of differences in efficiency in the LEDs used in these products, you never get true white.
The fixtures you see at a pro concert use a pure while light source and change colors by putting different colors of dichroic glass in the light path, the same way incandescent or gas-discharge fixtures work.

 

Edited by Dana_V
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Yes, that does help. 

One has to wonder if bands are having harder times making live pro videos when the clubs they play have LED lights. 

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20 minutes ago, Steve Haynie said:

One has to wonder if bands are having harder times making live pro videos when the clubs they play have LED lights. 

Absolutely.

Having said all that, and even though I work for a world-renowned lighting company, both bands I play in use Chauvet LED-based lights. They're lightweight, relatively inexpensive and we don't have to worry about tripping breakers in the bars where we play (like we did when we used PAR 38s). But man I wish they were brighter. Even video shot on a full-HD camera ends up looking murky.

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Another problem with LED's is that they act as point sources and the "point" is physically very small. That's part of why you can see it tiny LED from a large distance.

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26 minutes ago, HAMERMAN said:

Another problem with LED's is that they act as point sources and the "point" is physically very small. That's part of why you can see it tiny LED from a large distance.

Exactly. The viewing angle of a single LED is very narrow, and since the fixtures we're talking about are almost exclusively direct-view, even the wash fixtures create a relatively narrow beam.

To create a proper light source, multiple white LEDs are assembled in a cluster under a lens. This is a light engine from a typical modern fixture, and you can see the individual LEDs under the lens:

Light Engine.jpg

Once the source is established you can manipulate the beam however you want - color, shape, brightness (with mechanical dimming), etc.

 

 

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We used to play with 16 Par64's and twelve Par38's.  Had to plug the system directly into the electrical box pre-fuses.  Never blew out a building or "the room".  Our sound man was an electrical engineer, but we always stood in close proximity in case we had to save him.  No kidding!

I remember playing fourteen nights in a row at the Pier in Daytona Beach.  I wore sunglasses because the lights were so bright.  I looked like a raccoon by the end of the two week gig!

That being said, we now use sixteen Chauvet LED lights.  The stage is, in my opinion, a bit dim.  Five members of the band aged 57 (me) to 66 don't need bright lights like the "old days".  A little dim is just our thing.  Wrinkles and rolls hide in the shadows.

LED's might save energy, but they will never replace high energy lighting.   

 

 

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The memories of a hot nights in no AC bars steaming under 2 dozen par 64’s... takes a lot of beer... and bandana’s...

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I remember my son (now our sound man) asking, "you had those lights five feet above your heads?"  We all cracked up.  He immediately understood the heat they generated and why we talk about gigs being a "work-out" in the old days.  I'd lose five or six pounds on a back to back weekend!

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LEDs are a lifesaver for us fat guys - both in heat and in weight. Our light guy would get pissed when I'd re-aim the par 64s anywhere but at me. That was the worse part of playing out - grunting those heavy-ass lights in, standing in front of them for 4 or 5 hours, then having to grunt them back out.

FWIW: I replaced our mercury vapor yard light with a similar LED version and the first thing I noticed is the brightness. The LED is considerably brighter and whiter. Makes stuff look almost HD - clearer and crisper. But the other thing was the throw - while the LED was brighter, the mercury vapor light went farther. It sounds weird and I don't know how that can even work, but the LED doesn't stay as bright as far out. I was kinda surprised by that.

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On 6/17/2019 at 9:38 PM, The Shark said:

We used to play with 16 Par64's and twelve Par38's.  Had to plug the system directly into the electrical box pre-fuses.  Never blew out a building or "the room".  Our sound man was an electrical engineer, but we always stood in close proximity in case we had to save him.  No kidding!

I remember playing fourteen nights in a row at the Pier in Daytona Beach.  I wore sunglasses because the lights were so bright.  I looked like a raccoon by the end of the two week gig!

That being said, we now use sixteen Chauvet LED lights.  The stage is, in my opinion, a bit dim.  Five members of the band aged 57 (me) to 66 don't need bright lights like the "old days".  A little dim is just our thing.  Wrinkles and rolls hide in the shadows.

LED's might save energy, but they will never replace high energy lighting.   

 

 

With the exception of some high-output projectors, LEDs have replaced any other form of light source in the professional touring world. All of the major manufactures' fixtures are exclusively LED-based. It just hasn't trickled down to our level yet.

 

But anyway:

Are you sure we weren't in the same band? (haha)

In the early 80s my band used a massive setup of 500W PAR 64s (plus some other incidental lighting). Our sound guy was an electrician and would tap in to the breaker box pre-fuses. And yes, at least one of us would stand nearby with a 2x4 ready to knock him away from it if something went wrong (luckily, it never did). We had our own distro system. Maybe it was a little dangerous, but it sure beat tripping the breakers.

We also made our own pyro, and it's really, really amazing that (a) nobody got seriously injured and (b) we never burned any buildings down.

 

These days for me, though, it's all Chauvet, for better or worse. Four 4BARs with one band and two with the other. One person can literally carry all the lights in one trip. No more tripped breakers, no more tapping into the venue's electrical box, no more huge road cases filled with heavy lights and cables. And no more waiting for the fixtures to cool down before you can pack them up at the end of the night. It's smaller lighter, not as dangerous...but also somehow a little boring. And of course, no more homemade pyro.

 

For old time's sake: homemade pyro, 1981.

Pyro 1981.jpg

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On 6/22/2019 at 7:49 AM, hamerhead said:

FWIW: I replaced our mercury vapor yard light with a similar LED version and the first thing I noticed is the brightness. The LED is considerably brighter and whiter. Makes stuff look almost HD - clearer and crisper. But the other thing was the throw - while the LED was brighter, the mercury vapor light went farther. It sounds weird and I don't know how that can even work, but the LED doesn't stay as bright as far out. I was kinda surprised by that.

It's possible that the LEDs have a higher color temperature, making it look brighter – blue-white instead of the yellowish merc-vapor – but the actual light output (lumens) is lower, therefore the shorter throw.

I discussed it with one of the optical engineers at work and he added, "It also could be that the LED looks brighter because the light distribution is wider, but the axis intensity is lower than that of the mercury vapor light."

 

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That's what I love about this place - actual legit, that-really-makes-sense, answers. Thanks Dana!

Our band had its own pyro light guy and, during the KISS medley (of course!), went nuts with the flash powder. Placing over-filled home-made flash pots at the base of mic stands isn't the smartest manuever, but if you know it's coming you can step back and look away. Unless he misses the beat and goes early (as stoned-to-the-bejeezus-belt light guys will do), it usually worked out OK. Except this one time. Our other guitar player had just finished his backup vocal part and barely got turned when it went off. Singed his hair and burnt his arm pretty good (shoulda went to the hospital), but he finished the night. His mic stand was ash top to bottom.

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2 hours ago, hamerhead said:

Singed his hair and burnt his arm pretty good (shoulda went to the hospital), but he finished the night. His mic stand was ash top to bottom.

Damn he’s lucky! Remember what happened to James Hetfield?

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On 6/24/2019 at 1:14 PM, Dana_V said:

It's possible that the LEDs have a higher color temperature, making it look brighter – blue-white instead of the yellowish merc-vapor – but the actual light output (lumens) is lower, therefore the shorter throw.

I discussed it with one of the optical engineers at work and he added, "It also could be that the LED looks brighter because the light distribution is wider, but the axis intensity is lower than that of the mercury vapor light."

 

 

 

It's more complicated than color temperature.

 

MV, Metal Halide, and other such lamps have a color temperature, but the color temp isn't everything.  How that color temp is rendered makes a difference in things like color rendering index (CRI) and  perceived intensity.  So, if you look at a wavelength spectrum from LEDs (or other lights) they might have a pretty big spike at some frequencies, and just about nothing at others.  LEDs make "white" light by mixing different color LEDs, but if the component colors aren't made from LEDs that have a lot of different spectral colors may mix down to the "white" but will only have a lot of radiation in red, green, or blue areas and not a lot in between. Ones like this will have low CRI because they really don't produce all the wavelengths in between and so there's no energy of that color to be reflected back to you.  Good incandescents form legacy MV stage lights or MH systems (I used metal halide in my reef tanks, which is how I know this) have a more inclusive frequency spectrum.  

So, LEDs will often have a low CRI even if they have a perfect 6500K color temperature while a 6500K metal halide would have a very very high CRI. So, 100 would be perfect color rendering, like the noon day sun on a perfect summer day. Good old fashioned lighting would do a CRI of 95.  LEDs vary a lot by quality. Some as low as 65, some in the 90s. 90s is really darned good, 60s not as much.

Ones with lower CRI are going to photograph kind of poorly. You can shift colors to match full spectrum lighting with a different temperature, but you can't create a color that isn't there from a less than full spectrum light source. And your eyes will perceive the same thing, even though it won't be as obvious.

 

I hope that makes sense and I'm not just confusing people.

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5 hours ago, Moose said:

 

 

It's more complicated than color temperature.

 

MV, Metal Halide, and other such lamps have a color temperature, but the color temp isn't everything.  How that color temp is rendered makes a difference in things like color rendering index (CRI) and  perceived intensity.  So, if you look at a wavelength spectrum from LEDs (or other lights) they might have a pretty big spike at some frequencies, and just about nothing at others.  LEDs make "white" light by mixing different color LEDs, but if the component colors aren't made from LEDs that have a lot of different spectral colors may mix down to the "white" but will only have a lot of radiation in red, green, or blue areas and not a lot in between. Ones like this will have low CRI because they really don't produce all the wavelengths in between and so there's no energy of that color to be reflected back to you.  Good incandescents form legacy MV stage lights or MH systems (I used metal halide in my reef tanks, which is how I know this) have a more inclusive frequency spectrum.  

So, LEDs will often have a low CRI even if they have a perfect 6500K color temperature while a 6500K metal halide would have a very very high CRI. So, 100 would be perfect color rendering, like the noon day sun on a perfect summer day. Good old fashioned lighting would do a CRI of 95.  LEDs vary a lot by quality. Some as low as 65, some in the 90s. 90s is really darned good, 60s not as much.

Ones with lower CRI are going to photograph kind of poorly. You can shift colors to match full spectrum lighting with a different temperature, but you can't create a color that isn't there from a less than full spectrum light source. And your eyes will perceive the same thing, even though it won't be as obvious.

 

I hope that makes sense and I'm not just confusing people.

Thanks for picking up the torch on this one  - you've done a much better job of explaining it than I have.

And yes, it makes perfect sense.

Here's a chart that shows the different light engine options for one of the fixtures the company I work for sells, the SolaSpot 3000. All LED-based, but with different outputs. You can opt for the "Ultra-Bright" engine for 37,000 lumens at 7000k and CRI > 70, or the "High Fidelity" engine for 25,000 lumens at 6000K and CRI > 95. It's a compromise: brighter with less accuracy or slightly less bright with better accuracy.

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I appreciate you guys providing the great info for those of us who are less light literate.  

An old band I was in (in the 80s) the other guitar player was an electrician and used to do the tie right into the panel thing.  Our drummer, always looking to try to be cool, one night at a show put his drum set at the very front of the riser but of course he didn't think it through.  There was a decent light rig in this club and by the end of the first song, his arms were roasting because now there were lights pointing directly onto his arms from a couple of feet away.  He ran down to the mix position after the song and asked the guy to turn those lights off.  The rest of us could hardly stop laughing.  

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16 hours ago, Dana_V said:

Here's a chart that shows the different light engine options for one of the fixtures the company I work for sells, the SolaSpot 3000. All LED-based, but with different outputs. You can opt for the "Ultra-Bright" engine for 37,000 lumens at 7000k and CRI > 70, or the "High Fidelity" engine for 25,000 lumens at 6000K and CRI > 95. It's a compromise: brighter with less accuracy or slightly less bright with better accuracy.

 

Yeah, the color accuracy is mostly a big deal for filming.  Most still photographers doing portraiture will still use strobes because they have the highest CRI bang for the buck. You can get them super hot since it only happens for an instant, so the flash is ridiculously bright compared to an always on. 

Lighting that's constantly on is a lot harder to do that with. It would be a totally understandable compromise to have a lower CRI for a live performance venue  and make it much brighter for your dollar if you aren't expecting to be doing pro video, or if you intend to use the colors more than the whites. For photography 70 is pretty bad, but for creative stage lighting it's absolutely acceptable.

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On 6/11/2019 at 9:55 AM, Steve Haynie said:

For decades stage lights were high wattage bulbs with colored gels in front of them.  In the last 20 years there have been colored LED lights used on concert stages. 

A friend has noticed the same thing that I have.  When a club has LED lights it makes it harder to get good photos.  At the last show I attended someone else was bringing up the same thing in conversation.  Someone I know who does paintings and illustrations has said that LED lighting does not emit light the same way as an incandescent bulb.  One explanation was that LEDs are constantly flashing while a filament is consistent.  If that is true, then photos under LED lights would occasionally appear dark. 

Can anyone explain what is going on with LED stage lighting that makes it harder to get good photos? 

I recently finished a major project that involved an all LED lighting system.

144 Chauvet Pro lights in total.

These don't use colored lenses, they have clear lenses and change the colors of each LED cell individually and in any combination.

They're extremely bright but have a height limit that they can be effective at.

The ones I installed in the center cluster operate at 35 ft. high and 60 ft. from the stage lip.

The stage trusses stay at about 20 ft and the front of stage truss is at 35 ft.

I don't see any problems with pictures, but then it might be that the Chauvet lights don't have filters, but change each LED electronically.

Here's some shots from some concerts:

 

IMG_0468 (1).JPG

 

IMG_0460 (1).JPG

IMG_0445 (2).JPG

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Posted (edited)

Here's a closeup of the smallest intelligent light we installed.

Cleaning these are time consuming even though they are very simple compared to the Maverick Spots and the Hybrid Spots.

Each lens is part of the the deep honeycomb gridwork and attached by about 70 screws, so cleaning involves getting an alcohol wipe down there.

The Hybrid and Maverick lights are extremely complex but easier to clean the 12+ lenses inside.

After disassembling these and looking at their complexity, I see why even the simple ones are over $6k each.

 

58691215442__32D6D385-984C-4A0A-85A7-4024C8460726[1493].JPG

IMG_0528.JPG

58691207528__B4BB7B55-902F-4934-9DD5-A944F41BB006[1503].JPG

Edited by HSB0531
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