XP-G - why the doughnut hole?

[HassanChop!]

My .02: I have two of the Lighthound XP-G dropins, and both have a slight "doughnut hole". Still an incredible emitter!

 

[tre]

No doughnut holes with my XP-Gs

2 Quark 123-2s (OP) - Perfect beams
Solarforce P60 (SMO) - Perfect beam
Dereelight p60 (OP) - Perfect beam
G5 Maelstrom (SMO) - Ring-free but slightly darker center spot

That is exactly what I'm talking about.

 

[SCEMan]

That is exactly what I'm talking about.

Not a doughnut hole by any means and unless you are looking for it, you don't notice it. No worse than the SST-50 I had with an SMO...

 

[aau007]

Fenix LD40 and LD20, EagleTac T20C2 MKII, 4sevens Maelstrom G5, Zebralight SC60, Quark 123 regular, and a Dereelight Javelin are all lights that I currently own that have it (some much worse than others). There have been many other XP-G lights which I've sold that had the same issue.

It seems to be limited to the XP-G because I've not noticed this in any XR-E, XP-E, SSC P7, SSC P4, SST-50 or SST-90 lights I've owned.

I have an M31w on order so I hope it is as good as everyone says. That is about the 10th positive comment I've heard about this drop-in.

I will also be ordering the quad XP-G when the official sales thread is started.

Add Fenix LD10 R4 to the list.
Not exactly a donut hole but a darker center spot like sceman said.

 

[Henk_Lu]

Not exactly a donut hole but a darker center spot like sceman said.

You only see it if you do white wall hunting, but it is there on all my XP-G with SMO, like the Quark Turbo or the Nitecore IFE1.

I have to agree that for throw it is a trade-off, but on the IFE1 they should have put an OP, small lights are no throwers! The Quark Turbo is meant to be a throwy light and it is OK...

 

[jhc37013]

I don't even bother buying XP-G unless it has a textured reflector I've been fussing about donut holes for awhile now that nearly ruins a otherwise really nice light.

If you can see any type of dark spot while white wall hunting even if it's just a little than that loss of light is going to hurt the throw when using it outdoors, is that not correct? It's like my P20C2 MII and T20C2 MKII actually throw further with the OP reflector and it seems to be the same with others.

 

[siana]

My JetBeam - Jet-IIIM R5-SMO also has a think like a darker center spot, that can be seen even in the field.

 

[xdes]

I dont have donut hole (fenix tk12r5 smo. at least i dont see one) but have something like this. http://img820.imageshack.us/img820/3991/tk12beamhole.jpg

if you dont see it:
http://img824.imageshack.us/img824/2540/image1pox.jpg

slightly noticeable but it is there, a small darker area. and i only noticed it at short distances.

or is it donut hole? an ugly one perhaps

 

[tre]

I dont have donut hole (fenix tk12r5 smo. at least i dont see one) but have something like this. http://img820.imageshack.us/img820/3991/tk12beamhole.jpg

if you dont see it:
http://img824.imageshack.us/img824/2540/image1pox.jpg

slightly noticeable but it is there, a small darker area. and i only noticed it at short distances.

or is it donut hole? an ugly one perhaps

That is not doughnut hole - it is like a little pin hole in the middle. Fenix is the only brand I've seen that has the pin hole. My LD40 has the pin hole and doughnut hole. I think it may be an off center emitter? I had two LD20 with the XP-G R4 and one had the pin hole in the center and the other did not so it seems to have something to do with poor quality control.

 

[OneBigDay]

I have an LD20 R4 SMO that also has what I would call a doughnut hole. It doesn't offend in an outdoor environment, but it is there nonetheless.

I also have a Dereelight C2H that has a more pronounced doughnut hole but they were smart enough to use an LOP reflector. I was disappointed with the beam profile when I first got it, but in actual use (outside) it is great and I have no issues with the beam after using it for a while.

I have some Nailbender XP-G drop-ins with a perfect hotspots. I have a Dereelight XP-G drop-in with a very tight hotspot using LOP - really nice beam profile if you're looking for some throw.

Also noteworthy is the Jetbeam E3S beam profile. This one really surprised me. For a small format light I think the beam profile is perfect. More floody than throw, nice big hotspot, no doughnut hole, good useable spill. Well done IMO. Throws plenty but is not a thrower per se.

 

[IMSabbel]

EagleTac T20C2 MKII

I can only comment on this light: Mine does not even have a hint of donut. In fact, the hotspot is beautifully uniform.

Could it be that you want a gaussian hotpot and consider flat illumination as "donut"?

 

[ShineOnYouCrazyDiamond]

I have, or have owned, at least 10 different lights with XP-G leds and not one donut hole. Most of these lights are a bit higher end though so quality is to be expected.

Some lights have reflectors designed around the XP-G and some are mods from Seoul P4 reflectors - and they all look great.

I would presume that any lights with these donut holes are due to either poor or rushed design or possibly just bad focusing. If you can rotate in or back off the led a bit you may be able to focus it out. I have one or two lights which I re-focused a bit and they looked much better. If the threading was a bit loose because of backing out a threaded light engine I would just use a touch of blue thread lock to hold things in place properly.

 

[Napalm]

Resurrecting this now that the XM-L is widespread....

At the time I see that the doughnut was blamed on reflectors - lazy manufacturers that replaced the XP-E with a XP-G without adjusting the reflector.

However at this point I have 4 XP-G lights (recent models) that all have the doughnut (more or less visible) and 4 XM-L ones that don't exhibit any kind of doughnut - nice uniform hotspots.

Did the manufacturers suddenly get unlazy or was there really something going on with the XP-G itself?

Nap.