Just a general question,
can someone explain to me, why long thrower flashlight have often few lumens (or at least less than flood light) ?
I understand why long throwers have more candelas (sounds logical : more light concentrated in the beam), but I don’t understand why there are less lumens ?
think of lumens as a sphere, or globe. if you put the flashlight inside that globe, the lumens are the measure of the entire light hitting all parts of the globe.
Candelas, on the other hand, are just one point on the globe - how bright it is in one spot, which is what throwers are good at.
It’s to do with the control of the light into a beam, Vs brute force output.
Generally, thrower LEDs have a small light source, so it’s easier to shape that light into a tight beam… Downside is that you only have a small LED die so it’s limited output.
Big output lights often have big fat emitters, or multiple in small reflectors/optics, so it’s more difficult to concentrate the light into a tight beam, but you can have lots of lumens.
Ideally we would have thousands of lumens from an infinitely small point source, but physics of LEDs don’t allow that.
Usually there is a compromise between lumens and candelas, if keeping the same diameter. The size of a light’s optic or reflector determines how concentrated the light is (candela) and more LEDs means more lumens.
Usually a manufacturer uses a large reflector with one or a few LEDs for throwers, and many LEDs for flooders (small reflectors).
The other factor is that maximum throw LEDs are usually lower lumens, as they need to be very to prioritize high intensity (above 550lm/mm²) or use a very big reflector/optic.
There is basically just one exception to this rule, the Luminus SBT90.2, which has an intensity around 580lm/mm² and over 4000 lumens, but has the disadvantages of being very expensive, very power hungry, and makes lots of heat in turbo. You can look at the Emisar D1 (with SBT90 option), Wurkkos TS30S Pro, and Lumintop BLF-GT90 as examples of high lumen throwers, in different sizes. Lots of light, and it goes very far.
Interesting question. Just some random musings, not authoritative by any means.
Long throwers, especially SUPER-throwers, are mostly of single reflector or single TIR design, immediately this means one single LED. And the output is of one single LED.
Flooders could be single LED, like my ex Thrunite T2 with nauseatingly green XHP70.2 LED, but it doesn’t HAVE to be. You could add multiple LEDs by creating multiple smaller reflectors grouped together and increase output. This is seen with the lights in this thread of “super lights”: $100 Budget SUPER-LIGHTS w/ 15000+ lumens: Wurkkos TS32-Nichia 519a VS Chinese Power-Leds in Haikelite HK05, JKK76, Nightwatch Chaos
Long throwers COULD be multiple LEDs like those super lights with powerful Chinese LEDs above, all with throws above 700m, but it then becomes a floody long thrower. Problem is IMHO the near field bright flood causes pupil to constrict so now you don’t see that distant spot as well. Meaning it doesn’t work well as a thrower and that’s partly why the best long throwers remain single LED design that shine far field only - bright central spot surrounded by darker spill doesn’t cause pupil to constrict.
There are some super throwers with multiple SBT90.2 LEDs that are not floody. But they are big lights and expensive. They exist, just are not common.
Thanks all for your answers.
Finally it seems this point is not as simple/obvious as I thought.
Think about how bright that hotspot would be. You go blind real quick.
If lumens is the total light emitted, and a thrower with a single sbt90 and a huge reflector can throw for 2 miles with 5,000 focused lumens, or a LEP can throw for 2 miles with just 600 lumens, imagine you did the same thing but with 30,000 lumens. That’s basically a ray gun. There would have to be a no fly zone around your house lol