Then it’s 30% lower.
The above are at 97 yds to the red oil drum. Below, 610 yds to the white barn
My TK61, by comparison
They cut, raked and baled the field today. Other than that, same pic…same place same camera settings.
Is the TK61 bone stock?
It thread off at the control ring, above it I should say. Mine is off, and I’m about to hot de-dome it.
2 big strap wrenches and a persistent nature. 
With the stock light de-domed, I’m getting 420.5Kcd. Now THAT is what I’m talking about! My MAXToch SN6X-2X was king of the hill last month at 365Kcd. Now it suddenly finds itself in the crowd, watching the new podium holders.
SR90 at 622Kcd, TK61 at 600Kcd and the K50V2 at 420.5Kcd. WooHoo!
sorry heggood, didn’t realize that was directed at me…no, the TK61 is anything but bone stock. Carrier has had spring bypasses, running 2 tubes for run time, all springs bypassed. New driver in the head running 7.2A, XP-L2 on a 32mm Noctigon, de-domed, making 600Kcd. The reflector base has been cut out, such that it fits completely over a 20mm Noctigon. This helps it clear everything on the star, but now that it’s got the 32mm Noctigon it’s kind of redundant.
My old S1100 with a dedomed XML2 (only a T6, and it started as a 1C, so it's pretty ugly) kicks the stock K50's ass up one side and down the other. I think the K50's focus is pretty badly off, it only shows the 'donut hole' at a distance of 3-4 inches, the S1100 is showing it out to around a foot away from the wall.
This de-domed K50 shows the donut at about 6 inches from the wall. My TK61 it’s out around 6’. Not quite that far on the SR90.
?? I'm so confused...
- I thought donut holes were a bad thing? You would want the donut hole to be at the most minimum length? I thought?
- not sure how comparing a mod'ed de-domed S1100 to a stock light means much? I got a mod'ed Jacob A60 and a mod'ed T20 that out throw a stock TN31, but doesn't mean the A60 and T20 are better throwers or better lights.
Tom, I’m finding that the donut hole is specific to each reflector and the amount of throw it’s capable of producing. Maximizing throw tends to take the focus further out, leaving the donut hole considerably further out…or at least in a massive reflector like the TK61 or SR90. That’s one of the things I was having trouble with on the focus with the TK61, getting the beam convergence as far out as possible so it wasn’t crossing over and enlarging out at distance.
The reflector in my Courui gives a tubular looking beam, doesn’t seem to have that convergence at all.
If you have some space where you can shine the beam out to inifinity look at the beam from the light out, you should see a darker “V” in the middle out to 3’ or a bit further on the big throwers. That should be about the distance the donut hole disappears. Unless I’m missing something completely, and that could very well be…and not for the first time.
That “v” is quite evident in this picture, with the TK61 shining across the Mississippi River…
A massive carnival searchlight, notice the men standing beside it…. this is the kind of “into infinity” I was talking about. Check out how far the “v” goes out in the center of this huge beam!
The opposite of using a magnifying glass to burn a bug. There’s a fine point that the light is in convergence, then it spreads back out on the other side of that point.
You can see where the effect comes from with a piece of paper laid over the front...
Roche F6 XML2 10* TIR:
Roche F6 XPG2 stock OP reflector:
XinTD C8 XML2:
edit: The XinTD probably needs the LED moved farther up, you can see it's not using very much of the reflector. It's got a standard ~.035" thick centering ring, where the pre-built XinTDs use the much thinner adhesive insulator.
I’ve been looking at the formula for figuring the parabolic curve, and it would seem that this “v” shape we’re seeing is due to an imperfect parabola. This is probably also due to the fact that an LED does not have a point light source so the reflector is having to gather light from a broader source and collimate it into the cone we desire. Effectively though, the differences we’re seeing are probably the result of the success rate of different manufacturers at getting the curve right.
Dunno, I'm having a tough time seeing the V - I see convergence, I don't see divergence on the other side. I know with lights like the Shocker and HD2010, The kcd #'s would go up as that donut's distance got less. Maybe you are right about the big reflectors. I recalll rdrfronty testing lux at many distances and saw no difference from 15 m on out, but that could be the specific lights he was testing at the time. I don't think I've seen any one else test lux (kcd) at significant distances - takes 2 people of course and dark open space.
On my TK61, I got the head loose and dial in the focus simply by turning the head on or off. Doing this while aiming it at the meter gave me the top result, and that has the donut hole hitting at about 6’.
For testing at 15M, I put the meter on a tripod and the video camera on another, zoom in with the camera and watch the meter on it’s screen. 
Distance here is a non-issue. I have plenty of that. My driveway is 267 yds long.
Interesting bout the TK61 - never saw that sort of effect before, but pretty much all my measured tests were at 4-5 meters. The biggest lights I tested were the TN31's and K40.
comfy - those beam pics are nice! I think I sort of understand it - looking at the concentration. The XinTD C8 though looks a lot like the S1100, as far as where the brightest part of the beam is, closely around the center spot?
Well, I won't have much of anything to add to the mod thread. My mod will end up being mostly cosmetic. I will be sticking with the stock led/star and the stock driver. I replaced two of the three resistors, for more output, but that's all except for heavier wire and resistance mods to the springs. I also did add copper under the star and I shaved down the locating ring for the led, till it's paper thin. That's about it, but since my mulitmeter is acting bad and so is my lux meter, I won't be doing any testing of anything other than seeing if it turns on and changes modes.
Copper Heat Sink
Finished?? Nope, I ruined the battery holder
, so I will have to go buy one. Either that or give it away with no holder and let someone else get one. I still don't see why it fried, but it did.
Anyhow, I did get a measurement of 104,500 lux at one meter out of it using 4 18650 in series, with heavy wires, on the bench and it never dropped from there, for the two minutes I was checking.
That's all I can do. I have a couple meters coming and I will rig one up for amps, with some 12ga wire and see what I get for amps. I replaced two of the R120 resistors with one R075 and one R100.
Very nice looking light there O-L.