[PART 1] Official BLF GT Group Buy thread. Group buy officially closed! Lights shipping.

INCREDIBLE….good job to all involved, cant wait :+1:

Awesome pics! Hope they make sure to give that smooth reflector a freaking good polish, Like the K70 which looks flawless!

yep , would be a shame if they didnt get it darn close to perfect, to maximize the throe

May I ask if anyone can confirm that this GT light require battery total of 8 cell or we can run only 4 cell but will not get the full 100% performance & Runtime.
Thank you.

I read on the front pake that it takes 8x18650s or rather 2x 4x18650s right? that is a tons of capacity for a modestly driven small XHP35? I think i’ll use BLF GT’s massive battery as a battery carrier for my other light :smiley:

Pffft. You call that a beam shot?

I’ll show you a beam shot.



Mountain shots look awesome.

Yes four cells ought to work
In fact this proto is a shorty with only one carrier , we wonder if it ia because of easier prototype making and saving weight or why they did this.

Hmm TK, your 10m throw vs GT 2000+m. For portable light I stick with the GT. However do fly by for a nice BBQ :wink:

It requires 4cells in series (one carrier). The second carrier is in parallel to the first one. Making a 4 series 2 parallel configuration.

it’s a beautiful light and those beamshots are crazy. Never gunna deny that.

However, seeing that this is a deticated thrower, I can’t help but ask this question:

Considering the emitter is square and the reflector is round, is there some kind of engineeering magic that can be applied to the reflector to optimize the beam pattern for more throw?

I would imagine the light coming out of the corners of the LED are being reflected a few microdegrees away from the hotspot. Or is this an ignorable issue with such a drastic size difference between the size of LED vs size of reflector?

yes good question! I’d like to see the smart guys talk about this too!

Not a smart guy here, just grounded in reality and evidence. You saw the beam shots right? What in them gives evidence that what is suggested is a problem? There’s a huge difference between theory and reality as it appears to the eye. Or at least that’s my take on it.

no it is valid IMHO, square LED die n a round reflector
too bad no real round LED dies are common practice, would be great in zoomies

Hail to The King (of all flashlights)

Making a decent reflector at all within the constraints of our budget is very hard. The short answer is no, there are no magic bullets and voodoo for that. The idea is also otherwise implausible.

Light emitted further from the center point will not make the hotspot brighter. The emitter square shape is irrelevant here, and the concept may be more properly understood through the principles in choosing a suitable emitter. Luminous intensity dictates throw for a given reflector, and/or reflector size defines max. theoretical throw for a given emitter driven at a given current. A higher total luminous flux helps make the light more useful and more than a maximum range thrower, but will not make it throw further with the same intensity.

“Extra light” from corners of a typical square emitter(compared to a theoretical round emitter) will not increase throw, just like a larger emitter with higher output, same shape and equal intensity would not increase throw(while of course putting out more lumens, a different beam profile etc).

The nitecore PDOT reflectors are also not mirror polished, they lave rings in them, however when one BLF member hand polished it to mirror finish the lux massively decreased.
In order to have it polished even more, and not reduce the surface lambda, very specialized optic machining equipment is needed, which may not be available for a low-cost manufacturer like lumintop, or may not be capable of polishing reflectors of this massive size.

An optic will project a square image of the source of light, this is a lot clearer with lenses since the distance between the LED and lens doesn’t vary as much as with a reflector.
For this example, just imagine the clear square die projected by a lens.
The optic is focused at the center of the LED, but since the LED is not an infinitely small point it creates a spot with the shape of the LED,
However, all surfaces of the reflector are being used for all points on the LED, it is not like “outer edge of reflector reflects outer edge of LED”
.
In order to “bend” the light from only the outer edges or corners of the LED, without affecting the light from the center of the LED which is already going straight, a special optic that has different indexes of reflection/refraction depending on the incident angle would be needed.
I’ not sure if that material is even possible or exists, but probably not because if it was possible to take the light from the corners of the LED and bend it to the center of the hotspot that would be violating the second law of thermodynamics.
.
The reason a small LED and large reflector is used is because the bigger the difference between the two is, the more collimated the beam is and the more throw you get.

I wasn’t suggesting that it wasn’t a valid theoretical problem, only that it wasn’t a problem via the evidence as seen by the eyes.

I can’t tell you how many folks I have known who believe the theory, or the computer, rather than their own observable facts. It’s reality that trumps everything.

Please quote who you’re replying to, otherwise it makes the thread very confusing.
I thought you replied to me since you posted right after.

Goddammit, I don’t have enough money for the GT and the Q8 to ship at the same time d:

What you say is true. I doubt I can tell the difference between 700k and 750k lux even in a side-by-side comparison. That and there are surely going to be slight differences from sample to sample.

To me, lights like the GT have long since abandoned the constraints of practicality and their credibility is solely based on numbers. I’m sure if the GT’s final numbers were 2m lux and another company produced a light that advertised 2.02m lux, that latter light would definitely have more popularity.