LED lighting specs confusion

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Hi, I was researching some bi-color 1x1 LED panels but noticed that the IKAN light output varied significantly from the others. These are some of the ones I was considering:
Lightpanels - at 3 feet, the bi-color at 100% daylight is 1857 lux and 100% tungsten is 2109 lux - http://www.litepanels.com/1x1_ls_bicolor.php
Visual Buddha - at 3 feet, the bi-color flood for the 60 degree model is 2880 lux - http://cdn.shopify.com/s/files/1/0228/0437/files/Visual_Buddha_Value_DataSheet_8-26-13.pdf?358
Ikan IFB1024 - at 3 feet, the bi-color is 10344 lux - http://ikancorp.com/productdetail.php?id=656

If I’m reading the manufacturer specs correctly for the Ikan IFB1024, it seems the 10344 lux output is when the color temperature is at 4000K. Seeing as how the Lightpanels have listed their output specs when at the colour temperature extremes (full daylight and full tungsten) and the Visual Buddha specs don’t specify at what color temperature they’re basing their numbers on (I’m thinking they’re somewhere in the middle for maximum output), which bi-color panel gives the greatest output?

Is the Ikan IFB1024 that much more powerful than the rest, or is it because the specs listed are when the tungsten and daylight balanced bulbs are working together for maximum output?

Also, does anyone know the CRI value of the Lightpanels? Visual Buddha has listed their CRI as being 93+ and B&H (http://www.bhphotovideo.com/indepth/video/hands-reviews/ikan-featherweight-lights-lineup) have listed the Ikan IFB1024 at a CRI of 87 for the daylight bulbs and CRI of 82 for the tungsten bulbs.

Of the three, I was originally leaning towards the Visual Buddha lights because they’re light, less expensive than the Lightpanels, have a decent CRI rating, and seemingly have good output compared to other 1x1 LEDs I’ve looked at. However with the Ikan IFB1024 listing an output (at 4000K) of 10344 lux, it’s made me wonder if it’s significantly brighter than the competition.

I have some Lowel tungsten lights that I’ve enjoyed using but want to add some LEDs for quick setup/teardown, ability to use batteries, and durability.

Can you give your opinions about which lights seem like the best quality for the money? Thanks in advance for your help.
 
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Let's look closely at that 10,344 lux figure and how that would relate to real brightness in comparison to a 1000 watt soft box equivalent.
Firstly, LUX values don't mean squat if beam angle is not given in the specs.
I have a very small pocket LED flashlight that runs off 2 batteries and has a LUX rating of 32,000 at 3 feet distance. Guess what ? the beam angle is 5 degrees narrow spot. Useless for video but I can always widen that beam with a diffuser to 30 degrees. Then of course the brightness drops like a brick on water.
That 10,344 Lux figure must either have been taken so accurately to 3 decimal places, so I am assuming that is very true, BUT and a BIG BUT, assuming that figure was with the leds common encapsulation beam dispersion of 37 degrees, as most are without any panel diffusion, then we can theoretically calculate the equivalent LUMENS and from the LUMENS we can compare it with the filament 1000 W equivalents that seems the GOLDEN STANDARD of all lights. So calculating with this very convenient conversion tool here : http://www.ledrise.com/shop_content.php?coID=19
We can see that 10,344 lux at 3 feet with a beam angle of 37 degrees gives us 3,558 lumens.
As lighting goes, a 100 watt common kitchen bulb produces roughly 1600 lumens, therefore that light mentioned is 3,558 lumens / 1600 limens = 222.365 Watt bulb equivalent.
Kind of 777 Watts difference short from a 1000W bulb , don,t you think so ?
The ONLY way that light having the 10,344 lux rating and still be as bright as a 1000 watt filament is if the beam angle is 82 degrees when that lux measurement was taken.
they could have specified that , but I wonder why they didn,t....
 
Hi Norman, thanks for your informative reply. I'm sorry I didn't mention the beam angle of the other lights.

You've raised some very good points. It'd be easier if all the manufacturers reported results from standardized categories and conditions.

According to the Ikan IFB1024 Quickstart Guide (http://ikancorp.com/Downloads/quickstart/IFB1024_QSG--new.pdf), the brightness is 10020 Lux from a distance of 2 feet and at a 60 degree spread. However in the main product page for this light, it states that from 3 feet, it's 10344 Lux.

Shouldn't the light be brighter from a closer distance?

Also, on the main Ikan IFB1024 product page under 'Specifications' (http://ikancorp.com/productdetail.php?id=656), it lists 'Brightness: 3' / 10344 lux (± 100K) / 4000K (±100K)' with the 'Color Temperature: 3200K (±100K) / 4000K (±100K)/ 5600K (±100K)' and 'Foot Candles : 506.5/ 961.3/ 613.1'. Since it's stated to be a 60 degree light in the quick start user guide, that's how I'm reading it for now.

Contrast this with the 50 degree 1x1 Litepanels Bi-Color( http://www.litepanels.com/images/onesheets/1X1_ls_onesheet.pdf), at full tungsten setting and at 3 feet it's 2109 lux and 196 foot candles. At full daylight setting and at 3 feet it's 1857 lux and 173 footcandles.

Furthermore, the Visual Buddha 60 degree bi-color light from three feet is 2880 lux and 268 footcandles.

I don't know if I'm misreading the information, if the Ikan IFB1024 is THAT much brighter than the competition, or if it's being poorly represented from the manufacturer.

I do know that the discrepancies of the information available makes me less confident about purchasing their products.

Has anyone used the IFB1024 or the Visual Buddha 1x1 LED panels? If so, what are your impressions of them?
 
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bi color (the way most of them are currently made, with half the emitters being daylight and the other half tungsten) is generally speaking, a waste of your money. i mean they are handy as hell. but in my opinion not handy enough to justify losing half your power at either end...

get a daylight unit and a stack of CTO gels.
 
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i LOVE ikan. they have some of the better feature-per-dollar gear out there. they don't get the respect they deserve. and i think a good bit of that is because the way they present specs is inconsistent at best. not saying their reporting is wrong or intentionlaly misleading. but the consistency and manner in which its presented - IS.

i worked there briefly a couple years ago in a marketing capacity in hopes of turning this kind of situation around.
two years later. it's still mostly a mess
 
In general the bluer tinted leds are brighter than their warmer counterparts as the efficiency for the same amount of power or current going through them is greater. That is because less of the phosphor die and more transparent at that, is used to bring about the 5500K. In warmer tinted ones like 3200K, a deeper yellow or less transparent phosphor is used to achieve that 3200K.
Assuming a blue emitter in the 5500K gives out 1000 lumens of light at a current of 3 amperes going to the led, that same current going through an identical led but in the 3200K category will give out 750 lumens for a reduction of 25% in output.
Manufacturers of the units want to put the brightest leds into their products but unfortunately the warmer tinted ones are always less efficient and therefore the difference in brightness. What can be done is to throttle down the amperage a bit on the 5500K ones so that the output is equal to the warmer tinted ones. Thia can easily be done by adjusting the led driver circuitry to match. They don't do that because they want to have the specs high up there as a bright unit. I build some custom units that have equal brightness or lumens by doing just that. When both sets of 3200K and 5200K are on the current is divided equally between the sets but the overall brightness is greater because at half the current, the leds operate more efficiently and the lumens per watt is greater as compared with at their full power rating. Assuming that both sets give off equal brightness say 2000 lumens on the warm and 2000 lumens on the cool ones at full power each set individually. When mixed, the warm ones will give out 1200 lumens and the cool ones the same. Together makes 2400 lumens, each set operating at half power but now emit more lumens per watt at that current level hence the brightness increase. LEDs operate in a non linear graph and are most efficient at the lower current levels, as the current gets to the led's upper limit then the efficiency drop may be as much as 40%. It is nice also to have on the specs, among other photometrics, the lux value at a given distance with the beam angle at the maximum power (brightness) of the unit instead of saying a led unit is equivalent to a 500 or 1000 w softbox..??? what's that exactly.??
 
Meh, I'm done with traditional LED panels. Too many compromises. Remote phosphor is the future for LED panel lighting, and the sooner we all buy into it, the sooner it'll become standardised and cheaper.

Yes at the moment it still sits firmly in the buy-once-cry-once classification, but honestly, as soon as you've used it once - you won't want to go back.
 
One thing I noticed is the IKAN 1024 has photometrics essentially right in between those of the tungsten and daylight versions of Flolight's 1024 spot fixture, which has a 30deg beam angle. So this may be a similar but updated bicolor version of that 1024 LED panel? Or it may use the same LEDs but in a bicolor arrangement? It is probably about a beam angle of 30deg. Comparing to the other LEDs you mentioned, it makes sense that a 30deg LED panel would have about 4x the 3' lux reading of a 60deg LED panel with a similar arrangement of LEDs and power draw since it is focusing the same amount of light on an area about 1/4 the size. Beam angle is very important.


wgzn said:
bi color (the way most of them are currently made, with half the emitters being daylight and the other half tungsten) is generally speaking, a waste of your money. i mean they are handy as hell. but in my opinion not handy enough to justify losing half your power at either end...

get a daylight unit and a stack of CTO gels.
Click to expand...

I disagree. Arbitrarily adjusting white balance between tungsten and daylight is pretty handy. In so many LEDs there is a green spike and CTO just leaves you with even more green... I'd almost always choose bicolor over gelling most daylight LEDs even if it halves the output. Bicolor may halve the output at 5600 and 3200k, but then it'll increase the ouput at 4000k :)

Seems to me that LEDs are usually used for their convenience over quality of light or output per dollar, so bicolor to me makes a lot of sense as it makes them even more uniquely convenient. They don't have much output and they cost a lot and the CRI is almost always lower than fluorescent or tungsten, but it sure is handy to have a small led panel that can easily be powered by battery and dimmed from 0-100% and from 3200-5600k. They are great as lights for when you otherwise might not have lights because other lights are bigger, heavier and slower to set up and cannot run on batteries.

That said, of the panels listed in the OP, I've only used litepanels and wasn't all that impressed, if I recall it still needed some minus green correction and the price seems a bit ridiculous with so many other LEDs on the market now. Personally I'd always rather have a really spotty led panel since I can always spread the beam with some diffusion, but you can't spot an wide beam LED panel except by cutting the beam and wasting light. If it defaults as a spot it's handy for some extra punch when you need it. And the big gains you get in LEDs output over tungsten and fluorescent per lumen is partly from the efficient lenses they use.


I agree photometrics don't mean much unless you know the beam angle. If the power draw is similar, the luminous output likely won't be that different but it all depends on the beam spread, and beam spread may get all normalized to some extent once you put on some diffusion to soften and remove the shadow pattern.

The bicolor LED panels I've been using lately are half the output of the ones you listed. The 312AS which is way too green at 3200k and the Yongnuo YN-300II which I've been quite happy with especially for the ridiculously low price, despite lacking a DC input jack, so much so that I'm considering getting the new YN600's which are in the same range of output as the panels you've listed.
 
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