Choosing between SFT40 and 519a. Which one would be a better fir for this host and why? Looking for better tint, better efficiency emitter, longer and more sustainable runtimes. Either will be used with 5A buck driver, will go with OP reflector. Not considering B35AM as mcpcb are not yet designed for proper heat management.
SFT40 > 519A at 3000K. More efficient and less angular tint shift in a reflector.
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What if we take cri/color into consideration?
They have the same CRI up to sample variance.
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Have you seen a good source of efficiency for 519A 3000K? The SFT40 3000K is significantly less efficient than the 6500K. Per Koef3’s tests, a 519A 5000K is more efficient than an SFT40 3000K, but I’m not sure about 519A 3000K.
I haven’t seen a direct test of this emitter, but the datasheet suggests a typical 3000K 519a has 83% the lumens of a typical 5000K. Normalizing by this factor puts the 519A within +/-10 lumens of the SFT40 at 5A. The SFT40 loses some efficiency by being domeless, but compensates with twice the footprint for better thermals.
My real argument for SFT40 though is not efficiency, but beam profile. 519A domed really doesn’t play nice with shallow reflectors.
IMO you can’t go wrong with either. The few 519A 3000K I’ve seen have better tint (lower duv) than the few SFT40 3000K I have, but TIRs help with that.
TIR vs reflector does indeed make a huge difference in duv. SFT40 in a 20mm TIR is not a combination I see very often, perhaps because there is no tint shift issue that requires a TIR to fix.
I have an S2+ with the SFT40 3000K with a smooth reflector. I got it at the same time as an s6 with the same LED.
In the S2+ whenever you are white wall hunting or any wall hunting you will see multiple rings in the beam. If you are walking or moving the light around it’s not really noticeable. If you are standing still and moving the light slowly or stopped on things you will see it. It’s not the end of the world but it will bother some people. I’ve seen others mention the rings with this LED but again that was with a smooth reflector. The orange peel reflector will “probably” fix most of the rings. You’ll definitely get more throw with the SFT40.
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Are you me? Also recently bought both the S2+ and S6 with SFT-40 3000K and agree with everything that you wrote.
Only thing I’ll add is that even though I was initially disappointed with the ringy-er beam of the S2+, in actual use it is not very noticeable and the light has really grown on me.
With the S2+, there is so much variance in reflector quality, and so many different types of gaskets going around, that most of the time there will be beam issues no matter what emitter is chosen, though very small emitters like Osrams are more affected. With the SFT40 the stock gasket is good, so you probably got a dud reflector.
I just looked at three other S2+ and they all have a round protrusion on the gasket that sits up higher then the base of the reflector. On the SFT40 the square corners of the LED go out right to the edge of the reflecter so the gasket used does not protrude above the bottom of the reflector. Looking closely at the beam you can kind of see the squareness of this very center of the beam at 2 to 4 ft from a white wall. Shining the beam on the wall at an angle and rotating the light makes it even more obvious. I can’t capture it with a picture. So I suspect the rings are because of what’s going on right at the very base of the reflector.
That’s interesting, what type of gasket is it, round or square opening? Generally the squareness of the beam is caused by the square emitter, and that alone. If the ring is somewhat diffuse, it might be caused by the protruding gasket picking up light and becoming an emitter itself. Only way to tell is to turn the light on moon, put your eye at the ring, and see where the light is coming from.
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