LED lights and longevity?

E

eco_bach

Well-known member
Hi
Just picked up a Z96 off ebay. Looks pretty solid and a great deal. However, was wondering what the expected life is for these LED lights. What happens when you need to replace a bulb?

Are they meant to be disposable?(I hope not)
 
Led emitters do have a really long life expectancy in the order of 25000 to 100000 hours if they are driven within their amperage (current) limit that their engineers designed them with. Those light units that have many teeney weeney leds in them cannot be replaced if one or a few burn out, chances are they will never burn out . Leds are very finicky about the voltage and current being fed into them, it just takes a few milliamps more that they are designed to take and POOF !! out they go. They first take on a nasty bluish tint as they heat up and shortly afterwards (within seconds or less) they light no more. As long as the voltage input to the light is within specs, they should last a very,very long time. The leds are controlled by what is called a driver. Some drivers are constant current types that make sure the leds receive a predetermined dose of amperage that is controlled also by the dimmer switch. The real problem with led units is the low construction quality of the housing fixture itself. The leds will surely outlast the cheap plastic enclosure with the cheap dimmer potentiometer and the cheap way it is put together (CE quality control). I am not saying that all are cheap, but in this market you do really get what you pay for, Granted there are some units that you pay a huge sum for something that really should cost a fraction of what they sell for. Other things to consider besides build quality is the CRI index, smooth beam angle without or little light fall-off at the edges, input voltage range and the leds themselves. Really good units are the ones that have lighting class high CRI leds in them that do not have the green spike color cast. I do believe that the low priced multi teeny weeney led units are really designed to be disposable when you drop one, water gets in from the rain, the dimmer switch goes out, the power button goes, he battery terminals corrode, etc. etc.. The price to repair any of these malfunctions, and I promise they will malfunction BEFORE the life expectancy of the leds, will be HIGHER than to buy another unit. If you take for example a 25000 hout led and shoot on the average of say 2 weddings over each weekend with 2 hours of lighting each, do the math and you get over 120 YEARS of service. I would not worry about the leds at all but the associated electronics and the hardware that goes with them.
 
leds are a kind of scam if you judge by their longevity.
Yes , leds can have a long life, but unfortunately, the light output of a led is a bit like the one of the bulb of a video projector.
When new, the output is great, but the longer you use it the dimmer it goes and at about half their life, they should have lost half the power too.
There is one little excpetion for the first hundred hours where you can find a slight increase in brightness.
This is particularly true for led with high power output.
http://www.ledjournal.com/images/White_Papers/Philips_Understanding%20Power%20LED%20Lifetime%20Analysis.pdf

http://www.nickhill.co.uk/white_LED_life_expectancy.html
 
Last edited:
Scam? I don't think so, especially for all the advantages of LED lighting and cost (under $100).What would be useful of course is knowing exactly how many hours, at full brightness, before you get

1_ANY noticeable decrease in output

and

2 A decrease to half or more of the original output


Looking at the curve in the linked Phillips pdf, it seems there is a sharp decline but ONLY after 10000 hours!
ok, if I leave my Z96 on at full brightness for 8 hours a day, 7 days a week, that means that light output will only decline after 3.5 years of continual, 8hr day use.
With 'normal' use, I estimate this unit will last MUCH longer before any noticeable decline in light output.
 
Last edited:
The "scam" is not a question of their longetivity, but rather their performance for the price one pays. I do agree that they are overpriced, especially the ones ( lite panl) that still exhibit a low CRI along with a green spike and the fact that they output like a 50 watt halo bulb.
The bargain ones exhibit the SAME characteristics at a much lower price, but these you REALLY get what you pay for. Think about it, how much time will be invested in post to correct the off-color cast ? Why not get a good led with a good CRI (upwards of 85) and a metal/aluminum casing that will last and built like a light should be? I always laugh when I see one invest over 4K for a camera (without accessories) and the see this poor sap have a $79 "bargain" led on top of that.
 
Not familiar with the 'green spike' you mention as I haven't done any testing yet with the z96. But what do you recommend as 'a good led with a good CRI'?
 
Norman99 said:
The "scam" is not a question of their longetivity, but rather their performance for the price one pays. I do agree that they are overpriced, especially the ones ( lite panl) that still exhibit a low CRI along with a green spike and the fact that they output like a 50 watt halo bulb.
The bargain ones exhibit the SAME characteristics at a much lower price, but these you REALLY get what you pay for. Think about it, how much time will be invested in post to correct the off-color cast ? Why not get a good led with a good CRI (upwards of 85) and a metal/aluminum casing that will last and built like a light should be? I always laugh when I see one invest over 4K for a camera (without accessories) and the see this poor sap have a $79 "bargain" led on top of that.
Click to expand...

We've been doing a great deal of technical research and cost-analysis on LED as they've gained popularity. For all the issues people are experiencing with rolling shutter and low-end LED fixtures, it pays to do some research and find the truth about what is out there and how it will perform in the real world for video and other applications. Lamping a $400 incandescent 300w Fresnel for the equivalent of 25,000 hours will set you back more than $5,000. An "equivalent" LED fixture may cost $1,100 and effectively guarantee 25,000 - 100,000 hour performance based upon the IESNA LM-80 ("L70") standard, whereby the LED emitters are electronically driven at ~70% to guarantee output, color consistency and longevity throughout their rated life. If your LED fixtures aren't LM-80, you can almost be certain that the emitters are being over-driven and that may or may not indicate a shorter overall lifespan.

I speak with our manufacturers on these matters whenever I have the opportunity. Is there an upgrade / maintenance path for the LED fixture? Is it field serviceable or must it be sent in for new boards / emitters? LED fixtures represent the best technology we currently have available for many lighting applications, but there are many players who are content to put out very low-end units comprised of shoddy components. As it always is, you get what you pay for and it pays to do your research.
 
The green spike is a color by-product when one tries to use a tungsten (yellow) filter/gel to reduce the color temperature of a "blue" tint to balance it for tungsten illumination. Most if not all el cheapo lights with them teeney weeney leds in them have that famous blue tint in them as they are 5600K to 6200K more or less in color Kelvin degree temperature. Along with low CRI (color rendering index) and you have a recipe for the green ghastly tint that 1- is extremely hard to color white balance and 2-must be corrected in post.
I am not new to leds as I have been following them since the first ones were commercially available in high lumen output for use as general illumination. They have come a long way and it still amazes me how many on-camera led light manufacturers do not address this off-color issue. Like I said before, it is all for the profits as most of the led units in the range of 30 to 100 bucks out there all in the same category. I would not be surprised at all if them teeny weeney leds were originally designed for pilot lights in microwave ovens/on-off indicator lights for computers and a myraid of other household items Notice also that they have an encapsulated lens on top of them to direct the light forward and give you that spotty flashlight look.That is really to gain lux/lumens/intensity/brightness. How clever. Now there is hi CRI leds out there that have the high lumen/lux output needed for the perfect ( or almost perfect video light) They also lack the green spike and best of all disperse the light evenly without a center hot spot. You won't find these in the low price category. They do exist and affordable too. I cannot advertise the unit I use but suffice to say that it outputs 1800 lux at 1 meter, has a CRI of 90 at 3200K, covers a 70 degree wide beam without light falloff, is 3200K and switchable to 4200 CRI 85and 5600K CRI 80 at the flick of a switch, no gels/diffusers needed and uses only 4 leds in it. Oh, and it only draws LESS than 20 watts. Thing is, it is custom made. But it does exist.
 
Hello
I found the forum searching for "remove green cast" from LED camera lights
I am very concerned to find a nice on-camera LED since I paid twice for the wrong ones...
This is my odyssey:
I had 2 pieces of SONY HVL-LBPA LED lights. The color (with the conversion gelatin and the diffuser) was perfect!!! The only downside was the output was weak.
I then bought 2 pieces of another Sony-like light, I think it was Comer1800 hoping they were the same.
Unfortunately they produced GREENish light.
I then bought conversion filters AND diffuser from Sony in order to custom-make a sony-like light with the comer heart. I failed again and again.
Finally Sony announced a new model HVL-LBPB which had twice the amount of light with its predecessor but it was almost the same.
I was very very happy and ordered 2 of them (price over $500 each) just to find out they used the same LEDs with the comer one...:-(((((((


So I am asking....
Is there a good conversion filter to remove the greenish cast of the LEDs ????

@Norman99: could you please give us a clue?? I don't think showing a good LED is "advertising"
 
Last edited:
I have tried several LED lights and as some know I travel a lot and anything to save weight and space is on my must have list. I use Zylights the Z90 model.
http://www.bhphotovideo.com/c/product/652591-REG/Zylight_26_01008_Zylight_Z90_LED_DV.html
Great on camera lights, handy for a splash of colour, any colour on a background when I need one.You can control 2 lights from one position, Output is good in both daylight and tungsten, power consumption,which is what motivated me to buy Zylight, is excellent . They are expensive. I was not at NAB this year but from the reviews on-line with Ianero and Arri and Lowel getting into the LED line seriously I hope we see enough competition to bring prices down somewhat. But it will still be a "you get what you pay for " situation. I am sure that Erik is accurate in saying " Lamping a $400 incandescent 300w Fresnel for the equivalent of 25,000 hours will set you back more than $5,000." but if you do this for a living it is not about the long run as much as it is about the cost of doing business on a daily, weekly or yearly basis. My road kit right now consists of Totas and Chimeras and Cool-Lux instruments for the most part and lamping them is not very pricey and gets passed on to the productions one way or another like most "shooters for hire." All of this to say I think it makes sense for the rental companies to get into the LED market right away but I think I, like many, will wait and see a bit longer.
 
Last edited:
Can't really advertise at this moment. Been taken off too many similar sites just because I started posting actual pictures and specs even before production began. Only a few prototypes were shown without any model numbers or make. I was not selling or promoting them for sale at the time but only wanted member feedback for design and preference input that would be implemented in the final production. Sheesh ! I wanted to show the world a really well designed and made on-cam led unit and moderators took me off. A clue of what the unit (s) would be are in the post I started here: http://www.dvxuser.com/V6/showthread.php?244293-Your-thoughts-for-the-ideal-on-camera-LED
I don't want to be enigmatic about it but there is much more in building led units than just wiring them and powering them up. Leds do produce heat, and power class leds do produce lots of it, and is a major concern as to the reliability and longetivity of the leds. Led technology is still at a very early stage even though it is amazing at how far we've come in the past 2 years alone and many brand name mfrs. are still using old tech. leds ( more than 2 yrs. old) in their present lineup. Led output/brightness alone does not equate to good light quality, but too many look for price alone and overrated specs that influences the buying decision. Lighting is essential to both photography and video, wether it is done with or without any supplemental lighting. Many units do not come with full product specs. and will only tell the power consumption/voltage input/color temperature and the lux or lumen output. The beam spread uniformity and the CRI index as well as a photometric analysis is rarely given or found.
 
BrianMurphy said:
All of this to say I think it makes sense for the rental companies to get into the LED market right away but I think I, like many, will wait and see a bit longer.
Click to expand...
Price conscious buyers can look forward to conventional movie lights coming on the used market as LEDs move into the grip and electric houses :)
 
Problem is, LED lights just don't have very good color reproduction yet. Especially lights that use so-called "white LEDs". The American Society of Cinematographers just released a report that discusses the state of LED lighting, and it's not encouraging.

They did find that you can get better color accuracy if you use an LED light that makes its light from individual red, green, and blue LEDs and mixes them together.
 
If I can manage to leave my lights on for 25,000 hours of shooting, I will have no problem buying more lights and would love the opportunity. Is this a silly thread? If I shoot a full day, my lights might be on half that time on average. At that ratio I will shoot 6250 days to reach 25,000 hrs. At a very nominal $600/day, that is approaching 4m in revenue and take about 20 years to do. Am I planning to keep some LED fixture for 20 years? Now your mileage may vary, just sayin' a little perspective is in order.

Now the color issues are a bigger deal.

Grant
 
eco_bach said:
Hi
Just picked up a Z96 off ebay. Looks pretty solid and a great deal. However, was wondering what the expected life is for these LED lights. What happens when you need to replace a bulb?

Are they meant to be disposable?(I hope not)
Click to expand...

For $60 you smile if it lasted a year and throw it in the trash and buy a new one.
 
Leds used in our units are underpowered approximately 25% LESS than the maximum rated input amperage. Led output vs current is not linear as they all reach a point of diminishing returns at a specific drive current, meaning that over the "sweet spot" drive current the few lumen/lux gain along with extra heat generated is not worth the extra power (watts) consumed to attain the paltry 5% increase in brightness. Underdriving them has the added benefit of led longevity, as many mfrs overdrive or just about the max. current to squeeze as many lumens as possible. Over time, and can't say how long, overdriven leds lose their native color and eventually have a much shorter life than expected. Disposable leds are everywhere to be had for pocket change, but the color rendition, output, build quality is not there. All depends of course how critical your work is. If you make a living with your gear, get the right tools that you can afford.
 
The problem with incandescents is the heat. My latest shoot was in a home office. I live in Sacramento where 100 degree plus temps is not uncommon. Of course you have to shoot with the A/C off. You do the math.

I've used LEDs in this situation. One of the actors was a 'sweater' in 80 degree temps. Imagine several hot lights in this small room.

LEDs have two problems, apparently. The cheap ones are junk and the good ones are very expensive, much more expensive than incandescent lights.

Since I'm a 'late adopter' I've purchased the cheap ones and will wait for the good ones to come down in price.

Since I own a $1000 camera, I'm not in that 'stupid' group that owns a $4k camera and a $500 lighting set-up. I'll let you know if I win the lottery.
 
I have a couple of the 'cheap' smaller LCDs(Z96) and 1 'cheap' 500 LCD (Konova).

Still haven't done any testing to see if there are any green spikes.

At the price a great value IMHO.

Anyone know what the CRI is of the aforementioned LCDs?
 
You must log in or register to reply here.
Back
Top