BLF A6 3D wrong color temperature

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pauldb
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BLF A6 3D wrong color temperature

Hello,

I hope someone could give me some advice on this issue

I am an amateur photographer and I have bought 2 BLF A6 led torches to use as an additional light source for macrophotography.
It was important that they had a color temperature of +/- 5000 K because I have to mix them with light from other light sources (electronic strobes or daylight).
Before ordering them at Banggood I have checked the specs:
There are 3 different tints
1A = 6500 K (Cool white)
3D = 5000 K (neutral white)
5A = 4000 K (Yellow light)

So I have ordered the 3D type. I received the flashlights, good service!
But… the product that was delivered, had clearly yellowish light.
Yet, the packaging did say “3D”. So what is wrong? It could be a packaging mistake. Maybe these are 5A (4000 K) flashlights in 3D packaging. Or, it could be the wrong led, so a production error.

I’ve put some pictures her: https://www.dropbox.com/sh/v64hh3kgoz9kbv0/AABEDL9GMHlhmUgbSJfu13EWa?dl=0
- A standard neutral grey card as it should look at 5500 K.
- The same card lighted with the light form the BLF torch. It is extremely yellow.
- A photographic test image as it should look at 5500 K
- The same image lighted with the light form the BLF torch. It is extremely yellow.

I do not have all of the test equipment like a colorimeter, but with my camera I can also measure a custom WB and I then obtain a 3950 K color temperature.

I have tried with some CTB gel filters to increase the color temperature but no real succes. It is not only a matter of adding more blue. And the flashlights get too hot anyway to put a gel filter in front of it.

I have contacted Banggood but they do not really have an explanation. OK I could ask to have the flashlights exchanged but I’m afraid that I will just have the same problem again.

So I was more thinking of replacing the led itself. I’ve seen this on Banggood
https://nl.banggood.com/DIY-MCPCB-With-XPL-3D-V6-version-LED-For-BLF-A6-Flashlight-Body-Accessories-DIY-Accessories-p-1457302.html

The question of course is: is this 3D really a Neutral White led or also a 5A Yellow one? And is there a way of telling what is what? I have removed the led pcb from the flashlights. The only indication on it is “A1700 L”.

Of course I could buy another type of flashlight, but I do love this BLF A6, I did choose it for a reason: it is a small but extremely versatile flashlight.

Has anyone had the same experience with the led not being the right tint?

TIA

Paul

Hikelite
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I believe you expectations are not realistic from these “3D”, these neutral are not neutral if that makes sense to you, their CRI is not good either and even so CREE has that specific dual tint, which means the beam is simply made up of more than 1 Kelvin temperature at the same time.
They should be yellowish in fact these 3D and with that dual tint and also low CRI, not neutral as in no color as one would expect by reading the word “neutral”.

thisnameisvalid
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You’ve just discovered the problem with a lot of Crees LEDs: tint shift. The colour temperature and tint varies depending on the angle of the emitter. Viewed straight on the colour and tint should be acceptable (still poor colour rendering due to 70 CRI). At extreme angles the light is much warmer and greener; this is the light that hits the reflector and forms the spot. As such you get a warm, yellow center along with a cooler spill that may appear purple. The CRI of only 70 combined with the beam variation create a comparatively low quality light that is a poor choice for anything requiring accurate colours.

What you really want is a light with a high CRI (over 90 for photography) and low tint deviation across the beam. A light with a Nichia or luminus high CRI led would probably be a good choice.

pauldb
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I should have consulted you guys before buying the flashlights. OK I’ll look around for other flashlights with high CRI.
But it would sure be nice to have some of the specs of the A6 (size, one 18650 only, several power modes etc…)

Anyway the BLF A6 will be of use for some of my other activities, such as caving Smile

tx

Jerommel
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If you want zero tin shift, you need a TIR optic.
It would be nice if you had a constant current regulated driver too, so that the output is always the same until the battery is too low.

The 3A or 3D tint ought to be neutral though, not yellow.
It’s (i.m.o.) the best tint Cree has.
Judging by your test card picture, you did get 5D.
Also note the greenish hue of the skin tones in the picture..
That’s because of the lack of red in low a CRI LED’s spectrum.

So, what you want is a light like a Convoy S2+ with a 30° pebbled TIR optic, a Nichia 219C 5000K high CRI LED and a constant current driver that doesn’t use PWM for the modes below the maximum.
Simon form the Convoy store (Aliexpress) could probably assemble it for you, although i don’t think he has Nichia 219C in 5000K…
He does have TIR optics, he does have the 3 mode LD25 driver, which he can calibrate to maximum 2 Amperes fairly easily.

I’ll have a look where one can find 5000K 219C nowadays.

Jerommel
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Hmmm… I can’t find any..
I can find Nichia E21 and Nichia E17 though, but that’s not a standard package, needs a custom LED board..
They are very good LEDs though.

Hikelite
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Jerommel wrote:
If you want zero tin shift, you need a TIR optic.
It would be nice if you had a constant current regulated driver too, so that the output is always the same until the battery is too low.

The 3A or 3D tint ought to be neutral though, not yellow.
It’s (i.m.o.) the best tint Cree has.

Zero tint shift is impossible, besides the tint shift exist without any optic at all, reflectors, just have the LED in a room and see the rainbow of tints.
Low CRI and dual tint makes these LEDs completely useless if you want serious lighting.
These are not neutral they are yellowish greenish, etc. They are all over the place, we are not taking about imagined neutral or whatever manufacturer claims, they are not neutral as neutral goes.

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Hikelite wrote:
Jerommel wrote:
If you want zero tin shift, you need a TIR optic.
It would be nice if you had a constant current regulated driver too, so that the output is always the same until the battery is too low.

The 3A or 3D tint ought to be neutral though, not yellow.
It’s (i.m.o.) the best tint Cree has.

Zero tint shift is impossible,

So is a prefect circle or a perfect straight line.
That doesn’t mean we can’t want it or can’t get close enough.
Hikelite
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Take the “3D” LED put in on the table turn it on and see the dual tint. simple as that.

5000K 219C has no context, just recommending stuff like that where quality is needed.
Can be low CRI, high CRI, even if it is high CRI can be greenish, or to have a tint, or it can have a large MacAdam ellipse.

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You’re right, but i already said (like others before me) he wants high CRI.
The 5000K high CRI 219C LEDs i have / have seen are not greenish.
And yes, 219C has tint shift too.
So does the even better CRI E21.
Even the Optisolis has some tint shift.
So you want pebbled TIR optics to eliminate that to where you don’t notice it.

The only LED i know that has no noticeable tint shift of itself is the Osram Duris E5 0.5 Watt LED.
Not suitable for flashlights though.

MtnDon
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The Wuben TO50R is excellent for being able to render proper colors. Photography was one of the design criteria

http://budgetlightforum.com/node/69364

Jerommel
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Ooh… Not a cheap light ! Shocked
It’s nice though.
But i forgot about the LH351D.
Good option, but i wouldn’t know where to get 5000K ones at the moment.
[edit] Maybe the FW3A? [/edit]

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pauldb wrote:
I am an amateur photographer and I have bought 2 BLF A6 led torches to use as an additional light source for macrophotography. It was important that they had a color temperature of +/- 5000 K because I have to mix them with light from other light sources (electronic strobes or daylight).

Welcome to the forum.

Your realization that LEDs do not produce full spectrum light, is on track.

There are colors missing in LEDs that make them poor at simulating Sunlight, unless you seek out photography grade LEDs

a BLF A6 is not equipped with a photography grade LED, but it could be modified.

MtnDon wrote:
The Wuben TO50R is excellent for being able to render proper colors. Photography was one of the design criteria

http://budgetlightforum.com/node/69364

thanks for that link
maukka has the best LED color and tint info of anyone Ive seen. He also has some great light panels he uses for photography (maybe someone can post that link for pauldb to learn more about the differences between a cheap, low cri flashlight, and a photography grade light).

the LH351d tint lands above the BBL, as does sunlight tint

however, the R9 output of the LH351d, is not as good as some other LEDs..
here is an article about the importance of R9

The LH351d has green tint, and its Red Rendering is not as good as some other specialty LEDs, such as the E21a and 219b

here is a good photo to illustrate tint position… above the BBL in this case, aka positive Duv

maukka wrote:

and look at the R9 value (this is THE single most difficult color for an LED to produce, and “High CRI” does not address the factor of “High R9”… a LOT of High CRI LEDs are not High in Red output…)

maukka wrote:

Here is the 3d LED in your A6, note the negative R9
pic is a link to the review

maukka wrote:
pauldb
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Hi all,

Thanks a lot for taking the time to share your knowledge with me. I will study it in detail. I took a look at the Wuben TO50R and indeed it looks like the perfect light. But quite expensive and I would need two of them.
Now, I do not need perfect white balance but it should more or less approach sunlight or strobe color temperature. And I do not need extremely high output. Even 1000 lumen would be OK.

Would it be possible to modify the BLF A6’s? Can’t loose a lot by trying.

PS: If only using the two BLF A6 as a light source, I can correct the white balance of the raw images, no problem at all. But as explained I will use these flashlights also as an auxiliary light source (to lighten up shades for instance), mixed with daylight or strobes. Correcting that is nearly impossible.

Paul

Jerommel
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I would assume, for photography and perhaps the occasional video recording, you want to avoid hmmm… just about every aspect of a light like the stock A6..
I mean, the cigar shape and all is probably fine, although it can get quite hot doing 1000 Lumen, because it has a small surface area.
But then again, for our eyes, the difference between 500 and 1000 Lumen is not that big.
For the rest, i’d say make a list of what you need it to be able to do and what it mustn’t do, and go from there.
FYI, TIR optics are available in various beam width angles, 30°, 45° and 60° being quite common.
There are also triple and quad TIR optics out there (for triple or quad LED boards), for if you need more Lumen.

Jerommel
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Maybe get 2x Astrolux S41 with Nichia 219B or 219C, if they’re 5000K.
Those are quad LED lights, but have the same driver as your A6, but that can be swapped.
But at least you’ll have better LEDs than the LH351D, regarding the R9 values (red).
They’re not that expensive either.
You can find it here http://budgetlightforum.com/node/60338 , along with a coupon code, for just over $20 a piece.
Under it you can find a 18650 battery tube for the S42 / S43, or look around on Banggood for the S41 18650 battery tube, but they will both fit.
But that way you can get 2 lights with 4x Nichia 219B 5000K for less than 50 bucks.
You can diffuse the beam with diffuser film if you want.
Anyway, that’s just an idea, it seems like a good starting point to me.

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pauldb wrote:
it should more or less approach sunlight or strobe color temperature.

adjustable color temperature option:
http://budgetlightforum.com/node/67481
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http://budgetlightforum.com/node/47123

I believe you will be seeking a high TLCI rating

- Paul

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TLCI?

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The TLCI metric (Television Lighting Consistency Index) was developed as an alternative to address the shortcomings of the commonly used CRI when used with photography equipment. Because the way cameras interpret light is slightly different to how humans perceive it, the TLCI attempts to provide a more accurate prediction of color fidelity of a light source for broadcast use.

CRI tells us about how a light source renders colors based on human perception. CRI, however, does not necessarily paint a complete picture about how the light source might render colors on camera or on film. Thus, a light source with a high CRI is not necessarily a light source fit for use in film and photography. To this end, the TLCI (Television Lighting Consistency Index) was developed. The metric is analogous to CRI in that a high TLCI metric tells us that a light source will render colors well in a film or photography context.

- Paul

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OK after giving this some consideration, I think the better option would be to go for these small Lumecube 2.0 lights.
https://lumecube.com/collections/dslr-photo-video

As said it is especially for macro photography. I needed something small (so no big led panels) and directional (I am not a fan of too diffuse light when shooting macro – I have a ring strobe and don’t like it) and reasonable autonomy and high output (to be able to shoot with small apertures).

It was a bit simple, thinking I could do this with a couple of cheap flashlights.

Thanks all for your valuable advice.

Paul

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Whoa, that’s not cheap..
Maybe you should have a look at this then:

Jetbeam-FL-12-2835-LED-780Lumens-6Modes-Dual-Color-Light-HD-OLED-Screen-Flashlight-Fill-Light

links and coupons here:

http://budgetlightforum.com/node/60338

You can buy 3 of those for the same money.

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thanks for following up with what you ended up deciding to do
those look like great lights

I hope they work well for your application, and that you come back and share your impressions and a couple pics Smile

Merry Days!

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OK I will keep you informed, I just ordered a Dual pack. But there are a lot of reviews and videos around about these lights.
There is an alternative that is nearly the same (Litra Torch) and a bit cheaper.
https://litra.com/products/litratorch-2-0

Both have pros and cons.

A third alternative is the Mirfak Moin. Costs only half as much but some user reviews I read, did not convince me.
https://www.mirfaklight.com/

Paul

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The LED color information here and on the links is next level. I always wondered why some led colors look off. Especially in the reds.
Thanks.

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Interesting thread. I just stumbled on it since the 3D I received seemed quite green. Still quite a deal, but definitely not as neutral as I’m used to. I’ll try it outside when it gets dark.