Interesting. MF04 is Boost driver at 2.7A and GT is Buck driver at 2.5A. Maybe the Lumintop is using a D2 bin CW emitter instead of a D4?
I think both are supposed to be the same D4 bin xhp35-HI. I wonder if that 0.2 extra amps is giving the Astrolux a bit more output?
Each emitter bin from Cree has a 14% tolerance and we are seeing a 16% difference here. It’s probably a combination of the extra amperage plus variations in the particular emitter. I wonder if multiple samples would even out to show the Astrolux having a slight edge only from the 0.2A extra.
BTW, the extra 0.2A amp should only be good for about 50 more lumens.
I think try to measure at 20-25m. I tried to focus my GT and in stock form it has 900 kcd at 10m and from bigger distance it was even worse. After focusing I got 1170 kcd at 25m and from smaller distances it was worse. It was looked worse hot spot at distances under 20m but at high distances it was far more better with naked eye also.
I have 3 GT’s in my hand and all give the best intensity around 10m from factory. More distance will loose kcd. I think that is why GT has smaller hot spot because it is a bit over focused. After fiddling mine and added 0,9mm thickness to led centering to raise reflector I gained almost 30% in intensity but after that the hot spot was bigger and I got my best numbers at bigger distances. Maybe MF04 has different focusing but I’m curious what numbers you got at 15, 20 and 25m distance. I don’t have MF04 to test it and I will not able to buy one later.
It’s possible that both emitters put out about the same lumens, but the Astrolux reflector is slightly more shiny and reflects more light out the front or the anti reflective coating on the lens is a bit better. Reflectors and lenses can typically absorb 20% to 25% of the leds output. In general, bigger reflectors tend to absorb more of the light than smaller reflectors.
EDIT: could you maybe separate the threads for both group buys? I almost thought I was late to the game for the MF04S because I saw a huge list on page 1.