I had a donut hole with the 50.2. It’s not so much the gaps between the dies that make the hole, it’s the emitter size. You can mostly make it hard to see if you adjust the reflector depth. It’s not too noticable in outdoor use, unless you shine it on a building side.
You can also try and offset the emitter slightly to get the hotspot smoother.
I think the closer dies on the new emitters make the dark center, less dark compared to the older emitters. I have pictures if you want.
I’m assuming the xhp70.2 will be the same as the 50.2. Less noticable donut hole, but still there.
Here is the 50.2 at lower camera ISO levels with 2 different reflector heights.
With your naked eye the dark center is less noticable due to the intense brightness of the hotspot, but once you start moving the beam around you will see it again.
If you don’t care much about high distance/throw numbers, you can adjust your reflector height to give a better compromise between appearance and throw.
I’ve found a donut hole pattern always seems to give the best throw numbers.
This donut hole is only related to the height of the reflector. If its good focussed and centered, there will be no hole.
You will have this hole on single-die emitters too, if the LED sits too deep in the reflector.
So the donut hole is only a slight intensity drop towards the center of the hotspot, and to be expected because the quad die of the XHP50.2 is still not perfectly uniform. But it is nothing compared to the old XHP50 and even acceptable on a white wall.
You would need a “not so good” focus to minimize the darker center. IE, bigger corona and less max lux. The pics I showed above have the reflector height adjusted for almost max lux and throw with only a slight difference in height between them.
If I move the reflector out more, I can make the dark center go away. The corona gets bigger and the lux levels drop down, throw is decreased, but the hotspot looks much smoother. So you just have to choose which you prefer. Max throw or a smooth hotspot. I went back to a xhp70 and adjusted my reflector to give a smoother hotspot. I lose a little distance, but am happier.
I think I’m gonna try the 70.2 soon just to try it out.
I have a XHP50 C8 as well that I built years back. Right when the XHPs first where released I suppose. Surprisingly, the OP reflector didn’t give the best beam. I have an SMO installed that I think came from FT. I know there are different versions out there, and I’d have to crack it open to check which one it is, but it works fairly well. There is a slight crosshair dark spot but it kinda serves a purpose in my application… It’s on my 12ga pump with a homemade tape switch that’s switching a FET installed in the tailcap. It’s running direct drive off purple efest 18350s.
It sounds like yours is better focused then mine since mine is just a hole in the middle but no crosshair. I tried another centering ring and didn’t care for the crosshair so I settled on the hole.
I most likely could have improved things a bit more by playing with the focus but it was just a spare parts light that I was tossing together, I highly doubt I would ever use it anyways so I didn’t bother.
I do so want to put an xhp35 in a C8 with a boost driver though, just a matter of getting the driver and firmware for the new designs to work.
I’ll see if I can’t get some beamshots and pics posted of that light. Probably start a new thread topic and that’ll capture some of my more unique/scratch builds. I’ll post a link here when I get there…