What does this mean? I would assume the surface brightness of the emitters is a good bit higher than that. Aside from surface brightness, lux does not provide any information about a light source without a distance. The SI unit of luminous flux is the lumen, and luminous intensity, the candela.
I have a Viltrox panel with similar characteristics, but smaller (adjustable color temperature, CRI 95+) and I think it uses 5mm Yujis. Brightness adjustment is non-PWM. It's also meant to take a camera battery, but I converted it to use two loose 18650s. Model VL162T, $30ish on Amazon.
Lux is lumens per square meter. Candela is lumens per steradian, the SI unit of solid angle. At one meter, these are equal, unless the beam hasn't converged at 1 meter. Aputure provides the beam angle in degrees, for which it was surprisingly hard to find the conversion. Sure, the units aren't technically comparable, but we know they meant the apex plane angle, at least we do now that I looked up the correct term.
So a right circular cone (which the light produced by a rectangular panel isn't, but we'll pretend) with an apex plane angle of 25 degrees has a solid angle of 0.1489365798 sr, approximately. 4380 lm/sr / 0.1489365798 sr = 29408 lm.
And that can't be right because the power consumption is 30 W, and the theoretical limit of luminous efficacy is 683 lm/W. I'd expect an LED panel like this to be on the order of 100 lm/W for about 3000 lm from 30 W.
* BLF A6 (AKA Astrolux S1)
* Astrolux S41/Manker E14
* BLF X5/X6 (AKA Astrolux S2/S3/SS)
* Emisar D4, D1, D1S
* BLF Q8
* BLF GT
* Convoy S2+/C8 (new firmware version)
These don't all use the same firmware, but they all use an open-source firmware with high-frequency PWM, except that I think the BLF GT does not use PWM. A number of expensive custom lights use these too; those often focus on metalworking and exotic materials.
Firmware sources available here: http://bazaar.launchpad.net/~toykeeper/flashlight-firmware/t...
I own an Astrolux S41 (Nichia 219B), Astrolux SS (3A) and a semi-custom light I assembled using the A6 and Biscotti firmwares by ToyKeeper. I plan to pick up the Emisar D4 (Nichia 219C) and D1S (5D).