thinking about flashlights

I'd like to know more about the capacity to illuminate area evenly, which I think is referred to in these forums as "spill" or "flood" (Is there a difference? In any event, pending correction I will use the latter term). What's the standard way of measuring flood? As the diameter of the illuminated area for a given distance from the lens? It strikes me that I seldom see a line referencing flood in flashlight data sheets, as opposed to such measures as "signal visibility" or "effective range". Am I overlooking something or is this feature chronically underreported? Is there a standard flood that most of the highend flashlights discussed in these fora can be expected to deliver? If not, what is the range of floods you can expect from a basket of products? What lights have big floods? Is there a market for bigger and better floods or do most people prefer lights with tight beams that go far? Is there a simple mod that cranks flood up? What's the nature of the tradeoff between flood and range? With the square of the distance, yes? Are there other issues? Is this a trend in flashlight design? Am I getting confused between flashlights and floodlights and lanterns, in that if you want to buy flood, you're really not looking for a flashlight, because flashlights are really all about throw?

I'm interested in any comments anyone knowledgeable might have about this feature of beam structure, so please don't feel confined by the actual questions above.

I usually put the light on the floor, and estimate the angle of flood.You can line up one edge of the beam on a floor square (tile or wood), and the 90 degree thing is obvious. I am very used to measuring angles (optometrist), so it's pretty easy.

I like lights like the SL TL-2 LED (100 degrees), and the TL-3 LED (105 degrees), with their very even floods. They also have very adequate hot spots.

My Pelican M6 LED is a better thrower, but only has about 75 degrees of "flood".

A Streamlight Jr. Lux only has about 35 degrees of varied flood light. Throws well, but the others are better for walking around, or identifing threats from the side.

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fhapgood said:
Am I overlooking something or is this feature chronically underreported?

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Both under reported and under appreciated IMHO. There are many applications for which a wide, uniform, light distribution is ideal. One of the CPF resident gurus, McGizmo, showed quite a bit of interest in flood type beams awhile back. He even developed some reflectors for this purpose such of the "McFlood". Lately, it seems, he has given in to the seduction of high peak lux values /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/nana.gif

Eh, my Aleph 3 has decent flood at any ranges over 10-15 feet. Good spill at medium ranges, though that's limited more by the light the LE produces than anything. /ubbthreads/images/graemlins/grin.gif A Luxeon V would provide more spill/flood, but would reduce throw somewhat.

there's a slight difference between "spill" and "flood"...

the main part of the beam are the hotspot and the corona. spill is any light outside of the corona.

flood describes an actual beam style. which usually is a beam with a hotspot and corona of similar brightness. the importance is the brightness of the corona.

a good example of a flood light would be the Surefire L4 or the Streamlight TL3 luxeon.

i find that a pretty accurate way to find a good flood of light, is to look @ the number of lumens it puts out, then compare it to the lux in the center of its beam. if you find a very high number of lumens, but then a seemingly low number for lux @ the beam center, that's a good indication that the beam is spread very nicely. /ubbthreads/images/graemlins/grin.gif so going back to the Surefire L4 and Streamlight TL3, these things put out big lumens, but the center of their beams are between 600-900 lux. which is low, when compared to most other lights in their size and configuration. whether incandescent or LED. John's method would be much better if you had the light in your hand tho. but sometimes it can be a little deceiving, as the spill light can appear somewhat bright up close, but in use might be barely noticeable. but you can usually compensate for it by getting to know your light. /ubbthreads/images/graemlins/wink.gif

maybe i explained that badly. hm. sorry. maybe someone who hasn't been awake for 20 hours can explain it better!

but in any case, flood is a growing craze now. i much prefer a flood of light to a stunningly bright spot. that's why my most used lights are my Inova X5T-HA and my Underwater Kinetics eLED. they're not too bright for indoor use, but they're still adequate for outdoor use. they'll light an entire trail rather than just a patch, y'know? it's great. /ubbthreads/images/graemlins/grin.gif