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June 1st, 2009, 09:20 AM | #1 | |
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My view on LED lights
I haven't had the time to spend much time on this board lately, we are having an unusual busy year but I've seen many posts on LED lights and also a lot of frustration. After 40 years in this business I've seen products come and go, some of the good ones stay and the not so good ones dissolve into darkness. What I don't like is to have to readjust my techniques to accommodate a new product, manufacturers have to listen to us, give us gears that we can use an integrate with everything else we have, LED has not done that.
This is one of my posts on another boards on the LED subject. This board is driven by suppliers so I hope Chris keep it, this is the only way we have to communicate with manufacturers, the other is not buying their products. Quote:
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June 1st, 2009, 12:14 PM | #2 |
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You do get the option to buy 3200K LED's most people opt for the 5600K. I've been told, you don't get one light that does it all. On camera lights are mainly used in emergency lighting situations, one needs better lights to make a difference. I wish for a 500W pocket light that runs on fusion, anyone? Then again I can't afford any half decent lights and use hardware work lights :)
I would love to hear what you think of the Coollights LED600? |
June 1st, 2009, 03:57 PM | #3 |
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He talking about on camera lights. The Cool Lights LED 600 is in another class, size and weight and not at all considered to be an on camera light--its something equivalent to a 650w fresnel. So not intended as the small lightweight source used as on camera lighting and shouldn't be compared and contrasted or reviewed as such. Lots of people use the 5600K LED 600 outside in some actual daylight conditions and can get a decent fill out of it so there is no comparison at all to any small on camera light.
As a manufacturer, here are my thoughts on the subject, many of which I've said before. I don't know any other manufacturers that actually chime in on these boards so I may be alone here covering that side of things. LEDs themselves are evolving and as they do evolve the instruments we make out of them will too. We know of the shortcomings and actually write about them telling people of them before they buy. For this reason we have customers that are entirely satisfied because they know whatever the limitations of LED arrays ahead of time. We also don't think its possible to make on camera LED arrays that are all that great so we mostly work on producing the larger capability instruments. I can't speak for or influence what other manufacturers do other than by creating very competitive products that are popular and doing things the right way myself. You have to know the limitations of the different technologies and work around them if you want to get the advantages that LEDs give you. 1). Given that LEDs are like "miniature spotlights", which are not useful by themselves, but in combination with a lot of other LEDs they become useful (just as one pixel on a screen would never be useful), you're making a new kind of light out of a bunch of small spotlights so you do have a new kind of source that has to be used in other ways if you agree with the advantage this gives you. This doesn't lessen the utility of the light it just means its a different kind, to be used in different ways and knowing the limitations. No one light in the toolkit can do it all. You wouldn't want to carry a 650w tungsten fresnel on a large car battery array down the street while filming a walking interview. You can do this with one panel like an LED600 on a lithium v or ab type camcorder battery. Its entirely usable in a situation like this where you've got another person to act as the "human light stand" so to speak. You could use a small DC HMI par for this kind of thing, but is it as affordable? If you rent, I guess so. I don't view an LED on camera light as being all that useful outside at this point so that's why we concentrate on these larger type of units which are very usable when used as intended. Not until you have one point source large wattage LED will you be able to construct LED sources that mimic the behavior of fresnels with one single shadow and all that comes with that. We've experimented with some large LEDs (30w and higher) but they aren't ready for this kind of use for a number of reasons. 2). Daylight LEDs still have color rendering limitations and aren't full spectrum. There are workarounds (like using filters) for this until we get a better LED. When you're in a "power challenged" area, you may find that something like an LED panel is really the only viable choice given its size, weight, price and time it can run on batteries. 3). RGB or dual color panels are fine but in effect you may only have half or so of the capacity of the panel producing light depending upon the color temperature or single wavelength color you dial in. You can also take care of many of the CRI issues with a dual color or RGB type panel but at what cost? It's expensive if you need microprocessors to help you dial in a color temperature. I've polled people about this capability of a "dual color" panel (which would be less expensive than the RGB type) and they like it until they realize that to produce 3200K you may only have half the LEDs firing and only half firing to give 5600K as well perhaps depending upon what the upper range of the panel is. Most customers that would want a large LED array want all the power going out all the time. Thus, that's why daylight only large panels are all the rage now that they're becoming semi-affordable. People like the LED 600 and they also want a 1200 and even a 2500 which we have in the works. We also have an LED 256 coming not intended for on-camera use but rather as a compliment to an LED kit as a small spot to be used as a back / rim / hair light. This output capacity issue is also true for the more expensive RGB type panels. Each LED has a blue, green and red chip. Say you wanted a red single wavelength output to mimic a light with a red gel. Well you only get 1/3 the output of the panel because only the red chips on each LED fire up. Thus, its not entirely as you might think or as advertised in some cases. Since most will want to use different color temperatures of white light for the work they do (from 3200K to 5600K), you would need a huge and expensive array of RGB LEDs to make anything large enough to be usable once you believe that on camera lighting won't be enough for your uses. All that being said, we're experimenting with a bi-color 1200 and 2500 panel now and will have a limited offering of that to see how people like it with the full knowledge that all 3200K only uses about half the output capability of the panel. Last edited by Richard Andrewski; June 1st, 2009 at 04:44 PM. |
June 1st, 2009, 04:19 PM | #4 | |
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I'm looking forward to an opportunity to test the Arri LEDs to see if some of these concerns are addressed. They're only available to rental houses right now. I tested the Zylights for 32k color cast. You can read the results in another thread. As far as lumens you may want to try the Zylight Z90. I found it has more power than the panels. The Litepanels on-camera lights were good for creating the market but not my preferred light due to a few issues. |
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June 1st, 2009, 09:10 PM | #5 | |
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Seeing that the conversation went from on camera LED light to the larger units I'm re-posting this that I originally posted on another board. Again my view is based only on established products, something that has been around for a few years.
I have hundreds of professional around the world that count on me to give them a honest opinion, this is the way I see it. Quote:
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June 1st, 2009, 10:58 PM | #6 | |
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Nino, I understand your concerns and have shared many of them. However, it's also true that the energy use profile alone makes color-balanced LEDs an excellent new option once you get to know them. Yes, as small LED Obies and similar on-camera fill lights, they're are nearly useless. Only when you get up to something close to a foot square does the output make them practically useful. And yes, most of these lights are insanely overpriced. Paying $1500 - $2000 for a single panel is nuts. My advice is to try what I did. I ordered two of Richard's CoolLight panels in 3200k. Fitted with Sony V-lock mounts (Anton Bauer is available as well) these have become two of my go-to locations lights for the very reasons you indicate. The ability to move a fixture anywhere it's needed and achieve fast, usable light nearly instantly. The cost was a MUCH more reasonable $400-500 per unit (accessories depending) so one could assemble a 3 light kit for the cost of ONE of the competing panels. Yes, they work a bit differently from what you're used to. For instance their barn doors work as expected in the first 50% of their travel distance - cutting spill outside the beam pattern - but beyond that, instead of cutting light like a similar barn door on a tungsten fresnel, they mask rows of lights such that you get a venetian blind effect. It's just how they work. But those small inconsistencies are no match for the fact that a 650 watt tungsten fresnel, pulls 10 TIMES the power of a 65w LED array like the Cool Lights unit. And yes, in this size, the light is extremely usable. In fact, in my corporate practice, I'm noticing more and more national retailers chasing energy savings by installing high efficiency fluorescent overheads that output color-friendly warm light at about 3300 degrees kelvin. In these settings, the 3200 degree LEDs provide an EXCELLENT face fill and/or rim light. Again with all the advantages of weight and portability. So yes, LEDs aren't for everyone. But the technology is coming along very fast and knowledgeable manufacturers like Richard are making it much more affordable than before. So I'd recommend trying not to let your previous experience with what this technology is NOT suitable for - color your opinon about the whole class. For what it's worth. Last edited by Bill Davis; June 2nd, 2009 at 04:30 PM. |
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June 2nd, 2009, 02:00 AM | #7 | |
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How's it going Nino?
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Like you, I also like the Zylight innovations but there are hurdles to overcome with these new tools. At this point I'm not confident that LED's will behave like other lights in terms of throw anytime soon. I think they are another tool in the kit at this point. If only the temperature calibrations get nailed down 100%, having them play nice with other lights will be a big step. |
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June 2nd, 2009, 04:13 AM | #8 |
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I have been interested in LED lighting for years. I do think things have progressed significantly over the last few years. It wasn't that long ago that the idea of lighting things with a panel of low power consuming LED's was science fiction. I do agree though, that LED technology is not yet ready to become a main workhorse of this trade.
I like to follow the technology of LED's themselves, and there has been no slowdown of ideas on making more powerful, more consistent LED's. Richard has made some very good points & informed us quite a bit on the different challenges of making LED's into a light package that can be used in production. It seems to me that the real challenge is in making LED's that can put out enough light so that a useful panel does not need the hundreds or thousands of LED's to create enough light. I won't bore you with the details, but there are tecniques being developed that will eventually result in diodes that emit orders of magnatude more light than current versions. As these diodes become available, manufacturers will be able to create more powerful panels. This would make ideas like panels with multiple sets of led's for adjusting the color temp more viable, because even at half output it would create a useful ammount of light. Also the idea of a single LED that could compete with a small incandescent bulb would make the on camera light with a single source finally possible. One issue I am not sure will ever be resolved is the CRI problem. My understanding of CRI is that basicly in addition to the "primary" color temp, a high CRI light puts out lots of light above & below that color. LED's have a major disadvantage, because they emit light at a specific frequency, and almost nothing above or below that wavelength is created. It would take someone who knows lots more about filter technology than myself to figure this out, but would it be possible to pass light from an LED source through some sort of filter that would "convert" some of the light to varying wavelenghts? If this could be done I am sure it would be at the cost of some light at the primary color, but just maybe it would not cost so much that the level is too low to be useful. Another method would be banks of LED's that each put out slightly different casts, but banalced in such a way that the overall cast is of the correct color. I suspect this mathod may already be in use to some extent. All in all, the current products are definately way too expensive. As LED's develop, prices should drop, but it may be a very long time be before anyone chooses between a Lowell & an LED panel based on which is less expensive. I guess my point is that LED's are coming, but they still need some time to get ready for their big broadway debut. I do think there is light at the end of the tunnel. |
June 2nd, 2009, 04:23 AM | #9 | |
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I've had one for a couple of years that I occasionally use onboard my Steadicam as an eyelight--I've replaced the knob with a little 32 pitch gear and mount a Preston motor to it, then hand the remote iris to the DP so he can feather the output as needed. In this application, it's never the primary exposure so it's OK that the level is a little down especially when corrected down to 3200. I've been thinking about trying the Zylight 90 as a more flexible option, especially since the Zylight guys have offered to make me a custom one that dims all the way to 0 (the standard model does not) which is critical when passing by reflective surfaces. However I'm a little underwhelmed by the current softbox attachment (Chimera and speedring, a bit clunky) and would like to see something a bit more custom. FYI I used an interesting product called the Kisslite from Gecko; it's a small LED ring light with integrated filter trays and eyebrow. You can switch the LED clusters on or off in quadrants, plus dim the whole works and all of this locally or remotely. It comes with both 3200 and 5600 modules and can be field swapped quickly. It's not cheap but it fulfilled a need. We used it full-time on the recent ABC series "In the Motherhood".
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June 2nd, 2009, 05:23 AM | #10 | |
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Color temperature and CRI are measured on two axes that are mostly unrelated to each other. Color temperature is a scale of shades of white light with a bias toward red on one end and blue on the other. Some people mistakenly describe the red end as yellow but its "red" because of the ideas behind color temperature being all about a theoretical metal object being heated from red hot to blue hot, etc. The other axis which is a balance between green and magenta bias is not classically thought of as CRI but that's what it ends up being in practical use if you know something about lighting and think about it. People confound color temperature and CRI but as I said, they really have no relationship for all intents and purposes as long as the light is relatively full spectrum-like in nature. You can have a bad CRI with any reasonable color temperature in middle range and a good CRI as well. A light with a CRI of 99 would be like daylight, tungsten or carbon arc. They're full spectrum and what all other electronic sources (fluorescent, HMI and LEDs) are measured and benchmarked against in both color temperature and CRI. They are thus balanced between magenta and green. The CRI scale then becomes a measure of how far off a particular source is from one of these benchmarks. 99 being damn close and 1 being about the worst you can imagine. A light with a CRI of 90 has only a very slight bias toward green or magenta. A light with CRI 60 has quite a bias toward green or magenta. Its mostly toward green though. All these sources will tend toward green unless they are well engineered for CRI through whatever means necessary. Pushing it toward magenta through some means is the common way to fix the issue. Why magenta? Because magenta is across from green on the color wheel. You use the color across from another color to counteract that color and null it out. Push it too far and you end up with bad CRI thanks to too much magenta. You can have a 5600K light with a good CRI, well balanced for green/magenta and a 5600K with a bias towards green and low CRI. They're still both color temperature 5600K though. Some color meters may be fooled though by the green bias if they aren't well setup to read that axis. You can fix CRI with several means. 1). Simply balancing the phosphors in tubes with more magenta. 2). With correction filters placed on the lights themselves. 3). With white balancing (if its available to you) which not only does a great job of sorting out what color temperature you're working at and making white appear white but also balancing the green/magenta axis as well. We're lucky with digital mediums because for the most part we don't have to worry about these things and there are easy corrections in most cases. Things can get a bit confused for the white balancing when you have different types of light mixed together, but that's another story and problem. Single wavelength colors like pure red, blue, green, etc. are not measured in color temperature but are just measured by their wavelength (nm). Again color temperature only has to do with white light and how its color bias tends towards. As for color meters and their accuracy, I have a Kenko KCM 3100 and I think its pretty darn true for most of the sources I've tried it on. It agrees closely with what the sprectrometer / integrating sphere readings are, which is what LEDs, HMI and Fluorescent are measured with at factories producing them. It not only does a good job of telling you where you are on the blue to red bias of white (color temperature) but it also does a good job of indirectly telling you about CRI when it mentions where you are on the green/magenta axis and what kind of correction filter you may need to get you to balance. If you derive CRI from this it would be a guess though since it doesn't directly tell you the CRI value. An integrating sphere and spectrophotometer are the only instrumentation I know of that can truly tell CRI. |
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June 2nd, 2009, 09:22 AM | #11 |
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I will suggest that for run and go location production with a tiny crew and one or two actors, the LEDs are perfect.
Available light is largely used. The LEDs can be main light, fill, background, shadow casters, etc. They work outside but also down in parking garages, inside cars, in alcoves, and so forth. I have a couple of Richard's lights. They are fully dimmable, and there are 4 bank switches. They operate on AB batteries. I supplement these two with a prompter people cambat light. The the lights can be setup in seconds. And the can be carried around as continuous fill, etc. We are doing a location web series, and no other lights really can work the way and as fast as we are using these. |
June 2nd, 2009, 01:38 PM | #12 |
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In addition to all of the points covered, light output stats of leds are confusing and frustrating. There seems to be a desperate need to compare light ouput to a known entitiy i.e. tungston bulbs. The problem is that Lumens, Watts and even candlepower are not an effective way to measure output. Each LED is an individual unit that has a degree of spread. A 1 watt LED with a 20 degree spread will output stronger than a 3 watt at a 60 degree spread. A longer throw LED (20 degrees) is great at distance but will blowout everything up close.
When a commecial lighting company creates a light, it seems as thought they are trying to be all things to all demands and as a result not many have "hit" it yet. I made my own with long throw Crees and have been using them for well over a year. Yes they are powerful but they are easily controlled with diffusion material. Oh and I rarely used them on-camera. |
June 2nd, 2009, 03:20 PM | #13 | |
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Gary, I have a suspicion that this LED verses older technologies is going to turn out precisely like the debate I went through when all the "Professionals" argued that early DV was inadequate for pro work since it didn't have everything that the industry was used to in its current workflow. They were technically correct - early DV didn't have professional timecode, it's color capabilities weren't robust enough for keying, and even the picture didn't have the technical resolution of high level analog video of the time. In the end, NONE of that mattered. The benefits of Digital eventually pushed the old analog world aside. And the fact that LED has the proven ability to generate useable photons at 1/10th the cost of tungsten technology (and for that matter that color balanced fluors can do so at a 70% energy savings) will - in the long run - be the final arbiter. LED is very young technology. But not for long. What they don't do well at this stage of development will fall away. And sooner rather than later tungsten will go the way of the time base corrector. I don't like it anymore than anyone else. I have a significant investment in tungsten gear. But that doesn't mean I can't see the writing on the wall. At some point everyone WILL move to incorporating LED lighting technology in video workflows. You get to decide whether that will be earlier or later in the transition. That's the only choice I really see. It's the math. A 10 to 1 advantage in anything is just too big to ignore. |
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June 2nd, 2009, 04:01 PM | #14 |
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Interesting thread.
Indeed Bill, that's a great analogy. Beating on a technology won't make it move ahead any faster than actual circumstances will allow it to move. It will advance at its own pace and as knowledge about it can. And there's the cost curve and acceptance curve that all things go through as well before they reach a stage of plentiful commodity and the pricing falls. We are in the early days of this kind of lighting, but there are companies that are providing the pricing pressure already right now (hehe). You will have people that don't like change and will rail against it in any case. I remember when I started down the LED product development path in 2007 I wasn't terribly enthusiastic about it myself. At the end though, I came away shocked and amazed what those little solid state spotlights are capable of. The more I tried to apply old ways of doing things to the development though, the more frustrated I was. So, its like anything else. Your ability to use a new technology is only commensurate with your ability to exercise limiting beliefs. Said another way, you have to open your mind and also be open to change the way you do things. Not expecting to apply old ideas to new technologies. That just brings more frustration as you try to do things in old ways using new tools. Do the techniques of lighting change? Not really, we'll still have 3 point lighting, playing with light and shadow, hard and soft light (for drama or no drama), backlighting, key and fill; but the rules about how you do it may change as the fixtures change. So expecting an LED fixture to behave exactly like a single point source fresnel will bring plenty of frustration. Fluorescent, HMI/metal halide, and of course tungsten are far from dead. There will be plenty of people that prefer those for a while. We still sell quite a bit of that, but the LED products fly off the shelves. I got the message. They want LEDs and the benefits they bring. In one long sentence I can sum up why I personally like LEDs. They are far more powerful than lumen (or lumen per watt) specs can ever tell because they are individual solid state spotlights themselves (complete with source and lens) and should not be compared to light bulbs at all but to other types of fixtures. Bring your light meter and you would be amazed what you can get out of LEDs once you open your mind to it. I wrote a blog article on some of my discoveries about LEDs during the development process for our first LED product. It shows why the writing is on the wall. http://www.coollights.biz/wordpress/archives/72 |
June 2nd, 2009, 04:14 PM | #15 |
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I totally agree. It's the future and it's good. Just a little immature. I converted my tungsten setup to daylight cfl's plus I use the leds. It appears that most of my shooting these days has more ambient daylight then 3200k. If I need more light than that, I converted all of my tungsten with dichroic filters just in case. I love the low electricity draw and lack of heat in this new technology. In a pinch I can comfortably run my setup off my 1200 watt inverter in my car.
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