Will dedoming a zoomie also increase throw? Specifically, the UF SK98 clone with an LB emitter.
My second question is to do with optics; is it possible to design a sliding lens system with multiple elements that can re-converge the beam at varying distances or at least throw a nearly parallel beam out the front? Has this been done before?
I don’t know about the re-converging but , the dedoming works for sure , especially if you bump the amps a little. You may have to mess with the height of the MCPCB or emitter to get the focus optimal , but once that is done it makes a big difference (at least in the SK98 style light of mine) Mine still has a little bit of an outer ring , as I need to raise the emitter just slightly more I think , but it doesn’t bother me really and is not there when you have the focus more towards the flood mode.
The factory driver (1.3 amps) got thrown and replaced with a FET for around 4.1amps and then a dedomed XM-L2 U2 1A on Noctigon put in place of the aluminum board with U2 on it.
Here is a couple of beamshots from identical lights with the modded on right and the factory or stock light on left in each shot.
Distances are noted at top of each photo also.
12 feet
50 yards
115 yards
De-doming is good in a zoomy, although I know nothing about the LB leds, can they even be de-domed?
As for the lens thing. In theory yes, although probably not easy to build.
Have a look here:
Using multiple lens elements will not significantly help in getting beter throw, or better control of the beam, while loosing more light by reflections off the extra glass surfaces. That said, there have been reports of ’pre-collimating’lenses that do help in getting more light in the hotspot, but that results in a bigger hotspot and hardly or not into extra hotspot brightness.
The rule-of-thumb is that (if all else is optimised) hotspot brightness (‘throw’) is almost exclusively determined by the surface area of the largest lens of the projection system.
robo819, many thanks with the info and beamshots, those help a lot! One step at a time for me, let me dedomed/LED swap first without killing off the light 
Chicken Drumstick, that is a most interesting thread, but I guess it’s not exactly a parallel beam.
djozz, ah, that is exactly what I was looking for, a little miffed at the fact that we can’t have a true parallel beam