@TEEJ, Thanks, its great to have that kind of insight for the purposes that an S&R light are intended.
My SR90 sadly sits on a shelf gaining dust as I purchased it out of curiosity at the time and have never found a need for it other than to show off.
I'm very curious to know, however, if you have ever used HID lights for S&R and how you compare them for usefulness to the SR90 in this regard.
The HID's are great for some types of searches, albeit the run times are pretty limited for most of the handhelds.
I use HH HIDs as well, but really just for long range/small spot scenarios where I need a short burst of long range light. For a sweep of a wooded area, the beams typically don't have a good pattern when you need to look close and far in the same location.
Where the HIDs work best in searches are when they are used from a rig with a power supply. This solves the run time issue, and when searching from a rig of some type, typically, you are looking at greater distances anyway.
There are of course some amazing HID torches that might have some incredible range, over a mile in cases, etc...I just don't happen to have any. A natural issue when searching is that you need to be able to resolve your target. At over ~ 500 yards or so, your EYES become a limiting factor as well. Think of it this way...if there's a guy laying in the grass a quarter to half mile mile away, in broad daylight...with your eyes, would you notice him, and, if you could, could you tell if he was hurt, or armed?
How about in moonlight? Most of the listed ranges assume that you have 0.25 lux on your target as the definition of "in range"...that's about like moonlight.
The other eye related issue is that if your eyes are night adjusted, you are MOSTLY using black and white vision....you see almost no color. Add to that that you can't see straight ahead as well...the central ~ 2º of your cone of vision can hardly see in the dark at all compared to the other 98% to the periphery. So, normally, in bright day light, looking at a guy a half mile away provides a target that you can focus on with your sharpest 2º vision (Fovea), and with color information. With night adjusted vision, a half mile away in essentially moonlight scenarios...you are limited to peripheral vision and very little color info to resolve that target.
IE: When searching in the dark...you look to the SIDE of a suspected target to see it better, where your eye essentially gathers light better. (Rods working better than cones in the dark....).
In search and rescue for example, one issue that really catches newbs is the POSITION a person might be in when you shine on them. Most people expect to see a man standing, sitting or laying down....and our eyes are looking for patterns that are associated with that. In reality, the body might be wrapped around a tree limb, half under a rock, and/or twisted into a more pretzel-like shape. When you sweep a light across them, the brain doesn't register what its looking at...the arms, legs, head are not where they "Should be" to register as "a man". The smaller the spot of light, the harder it is to get the CONTEXT of what you are looking at....and the harder it is to realize "HEY, that's a man!"
Of course, for HH lights...the lumens can only travel out there so far w/o dissipating...so, you are compromising between range and context. If you have amazing range (Aspherical lensed lights for example), you typically have a teeny spot of light. If you take the same lumens and spread them out to give more context...you don't have much range left. So, the compromise tends towards proportionally larger heavier HH lights with large reflectors...to get as much context downrange as feasible.
This is a long suit for the SR90. Its hot spot is pretty large considering the range, and the form factor can be carried for hrs on a long search. The TK70 and the VPT I mentioned have similar characteristics, but with a context bias over range, while still having great range. This is WHY I dedomed the SR90, to concentrate its smaller amount of total lumens to work with, stealing from its generous spill into a tighter, longer range pattern...into its hot spot....putting more lux on target at range.
Add it all up, and a night search is not easy....having to look near you can glare on nearby objects, reducing your night vision, so that when your light sweeps out to further distances, you see less, and the reduced amount you CAN see is further compromised by not being able to focus as well on distant dim targets.
This is one reason we tend to divide searchers into near/far roles...so one group is primarily beating the bushes so to speak, and the other group is sweeping distant targets....and together they overlap a search area.