curious, has a group buy ever been done with/thru Simon? Seems like he cares a great deal about end users needs and wants, and knows FLASHLIGHTS. I think the interest in a Convoy H1 headlamp with special emitters and those great UIs would be off the chart.
Do you already know what optics you would like to use? It would be great if it was compatible with Yajiamei optics.
For example with this: Frosted Yajiamei optics
Then, my suggestions for 20mm × 12.8mm Yajiamei optics:
Clear surface:
- all of them should be checked for each unique LEDs to be used with, because beam artifacts would be visible depending on light emitting surface shape and textures
- also, less suitable to mix tint of the LED
- 5 degree variant gives the most throw
negligible spill outside the hotspot, most of the light is focused in the hotspot (or there is a small corona as well)
Beaded surface:
- handles the different LED emitting surfaces very good, mixes tint better
- negligible spill, but it is a bit more than spill of the clear surface, also, slightly textured
my personal choices: 10 or 15 degree gives very good throw; 25 degree is the best for general usage; 38 degree is a bit floody, above that, definitely floody, but still defined hotspot
Frosted surface:
- handles different LED emitting surfaces very well, even the worse ones (best tint mixing ability)
- much more light is present in the spill
my personal choices: 15 degree gives a nice, conical profile gradually strengthening hotspot, 30 degree is already noticeably floodier; 85 degree feels like an extreme flooder (almost no hotspot perceived)
I regularly use Yajiamei optics in S2+, so my recommendations would go for:
flashlight: 10 and 25 degree beaded, 15 degree frosted
headlamp: 38 degree beaded, 30 degree frosted (also, 60 degree beaded and 45 degree frosted, if more flood is required - e.g. for close range hand work)