550 kcd = 550,000 cd = defined as the brightness at 1meter distance
Throw distance is defined as the distance at which the brightness is reduced to 0.25 cd (=about moonlight illumination)
So at throw distance the bightness has decreased 550,000 x 4 = 2,200,000 times compared to 1 meter distance
Brightness decreases with the square of the distance, so we need to take the root of 2,200,000 to arrive at the throw distance, this is 1483 meter.
This is true, but the standard specs use 0.25 lux. So people stick with that, to make numbers comparable across the entire industry.
Yes, it will probably be the pencil-est of pencil beams. At 550 kcd and maybe 800 to 1000 lumens, that’s 550 to 687 cd/lm. So the beam will probably be even tighter than the BLF GT. It has slightly more cd/lm and the reflector is smaller, so we can expect this one to perform extremely well at a distance but won’t really be useful up close.
Basically, it’s optimized specifically to be as “pencil beam” as possible.
Would be great to see the light offered with XP-L HI and SST-40 as well for more options in beam profile and tint. A CC driver hitting ~5-6A at max would be perfect for those as well.
Yes, the metric used to quantify beam shape is “cd/lm”. Here’s a rough guide for what that means.
Assuming XP-L HI in each light (except D18 and D1S V2), Emisar’s products go in this order from most floody to most throwy:
light bulb: ~0.1 cd/lm
D4: ~4 cd/lm, ~4300 lm
D18: ~4 cd/lm, ~14000 lm
D4S: ~11 cd/lm, ~4500 lm
D1: ~33 cd/lm, ~1300 lm
D1S: ~100 cd/lm, ~1300 lm
D1S V2: ~600 cd/lm?, ~800 lm? (TBD)
laser: ~10000 cd/lm
For general-purpose “EDC” style use, people mostly like items in the range of roughly 3 to 30 cd/lm, with the D4S’s 11 cd/lm being a very versatile balance. The D4S is a bit large though, so I’d really like something D4-sized or smaller with a single emitter and a ~10 to ~15 cd/lm beam.
I generally use the D4 most because it’s the smallest and has a clip, but the D4S has my favorite beam of the bunch. The D1 is also handy since in 18350 form it’s small enough to forget about in my purse until I need it, and it’s throwy enough for almost anything I ever need.
With D1S and D1S V2, they’re extremely good at what they do, and are unusually compact for the amount of throw they achieve… but it’s rare that I ever need or want that much throw. For people who do need it though, it’ll basically leave almost everything else in the dust, especially for the price.
550 kcd sounds right. I have a 72mm head with a oslon black and it only does 550kcd.
But I wish he would give us a rear clicky. Side clicky are nice if it was a high output thrower. But for a pencil beam dedicated thrower, a rear switch is better imo.
Rear clickies have two disadvantages: restricted UI choice and internal switch resistance.
That 1st point is obvious.
That 2nd point is having a good enough switch to support high current is quite expensive. Well, compared to an electronic switch anyway.
There’s something less obvious though: standardization for Emisar lights.
By only using e-switches, it makes it easier for them in terms of making stuff, and less overall costs.
Well he can just price it higher. I’ll happily pay even $85 for it. The performance of that thing is crazy…slightly more throw than an XHP35 HI with over double the output.