Accurate brightness measurements are for comparing one light to another. Thats it.
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I find what you say to be very true from my use of throwers.
My water cooled light burnt a 6500K led so I purchased a Digi-Key XHP 70.2 5700K, dedomed it, and it performed much better than the 6500K.
Guessing after dedoming it, the color was a little more than 5000K, but you could see more clearly down range. So now I will not purchase anymore 6500K leds.
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I have tried my throwers at many places, but it is difficult to find the perfect spot to see distance and use Google Maps to get some rough numbers. There is always some interfering lights. Took them on vacation to Pensacola, Fl last yr with a spot picked at 1 mile on a yellow building with street lights beside it. You could see the light on the building faintly, but pictures would not take because of the street lights. By the numbers at 1.372,969cd and 2,343m throw or 1.45 mile, it would be short about 30%, roughly.
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This is a very good thread, Thanks Dave 1010 for starting it ! :+1:
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I have decent eyesight but realistically you need an optic to see any detail at night over 100m’s. I couldn’t see a pig & 200m in daylight. But these Osram convoys are making fine light weight hunting setups, if Simon tweaked a few little details he could make one heck of a hunting light for the money.
His new L21B is the same dimensions as the L21A, but weighing in at 210g vs 354g. This is designed mainly for mounting since the cooling fins are minimal making for short bursts on Turbo.
I asked Simon how much it would cost me to get him to design a hunting model for me. The MOQ was 1000pcs, BUT he said he’ll do it for free since he wanted another hunting model. I was so shocked because no company would normally do that. Unfortunately, the focus isn’t as good, but that only drops the range down to 1,250m vs 1,325m which is nothing. If we’re taking the ANSI range and halving it, that’s 35m less.
The center hotspot doesn’t smooth out into the corona so well because of the focus issue, but I’m not disappointed. To be able to get something this affordable which is mountable is awesome. The body is 26mm allowing it to fit into most, if not all, 1 inch (25.4mm) scope rings.
Here’s my photo
I don't have use for it myself but that is really awesome of Simon to do! Not a huge surprise, I guess, considering all he's done. Are there any weapon-specific treatments like potting or stiff double springs?
I disagree with that statement. It’s like saying a rifle is always more useful than a shotgun. Try killing a flying bird with a rifle.
Throw vs flood should be a question of preference and more specifically application.
Try using an LEP while walking in pitch dark with no moonlight. It’s like not having any light at all.
I haven't needed to pot the driver for the hundreds I've sold, maybe it depends how powerful the gun is and what the recoil is like, not sure. I always install dual springs though. The 8A driver has a brass contact, so I remove it and scrape off the surface of the pcb to solder on springs. A button top battery is also required
One thing we need to remember about this standard is that it was driven and accepted mostly by trade organizations, not us end users and enthusiasts. That's why I've sometimes still been a little puzzled at the seemingly ridiculous parameters they settled on. I wish I could see the full testing protocol somewhere to see if that would shed light on things. I didn't pay close attention to when all of this was being discussed many years ago but since people and these standards organizations are not stupid, it makes me wonder if certain devices benefit from the parameters (and this would of course only be a benefit in marketing/sales). For the average consumer, it's confusing or angering because they buy a 200m light and discover that it's only usable for half that distance...even worse with battery run times although that's gotten a little better with most manufacturers, although still not straightforward to the average consumer. But y'know even if they were to change the standard parameters a little, clueless or unscrupulous marketers would still try to focus on the wrong things (like 50,000 hours "bulb" lifetime and eight years of run time on moonlight...).
Change in the standard would benefit consumers, I think, while still remaining just a comparison tool for those with more than one light or an interest in the technical side of things. What to do with that light and understanding vision, spill, "dirty" air, etc. still needs to be learned and understood by any user but that's just like basic life experience/education in other areas. But if Joe wants to light things up reasonably well at 150 feet, Joe should have a reasonable expectation that a light that advertises 150 feet will do the job without having to understand some science or standards or do math to adjust. Also...as long as these standards are all voluntary and the measuring equipment isn't standardized or required, much of this is still a no-man's-land in the marketplace when someone doesn't feel like playing the the same rules others do, and that never stopped even when the standards were adopted.
Gotcha. I thought Simon was doing that kind of thing out of the gate. So what we have is a great form factor for the purpose but tweaking still needed. Host looks pretty nice.
Any thoughts on if the ratio between ANSI throw and visible distance increases with distance?
Eg if you can see well at 100m with a 300m thrower (1:3 ratio), are things lit up just as well at 200m with a 600m thrower?
A customer wrote a review on the Convoy L21A CULPM1 and he said that through his scope he could clearly identify a deer, antlers and all, at over 600m. The range spec I measured at 11m was 1,325m. This is why I go by the half of the ANSI rating as usable, but only on an ideal night
What do you think could have a non-linear effect? Maybe our eyes, but is there more to consider? Particles should make a constant factor.
The inverse square law, of the light reflecting back to our eyes again.
A surface lit up with 0.25 lux is like a light source itself. If you double the distance between your eyes and the illuminated surface then there should be a quarter of the light hitting your eyes.
If my physics is right then this would be the case with diffuse reflection but specular reflection (eg from a retroreflector) would be linear.
I could be totally wrong with this.
Not really getting this. When you shine a light on an object (say a wall) 100ft away. Its the optics in the light that get the light to the wall. Isn’t it the optics in your eye that enable you to see it? This is predicated on you being able to see 100ft away. If you can only see 50 ft maximum, then you wont be able to see the light on the object, the light however will be there.
The light gets weaker and weaker the farther it travels. When it travels far enough, you can’t see it at all. This is why some stars are visible and some are not.
Isn’t this kind of what you are talking about?
Almost. Maybe I’m completely wrong but when there is 0.25 lux on a surface then that’s the measure of photons that get reflected off that surface. So 0.25 lux on a surface is the same number of photons from a flashlight 50ft away as 100ft.
Say 0.25 lux is produced by a million photons reflecting off the surface. I have no idea how many it actually is but that makes the example easier.
So now we have a million photons coming from the light source. These spread out in a hemisphere (similar to a 180⁰ beam angle). How many photons hit a detector (like eyes) then depends on what proportion of that 180⁰ the detector covers. If our eyes are twice as close then they detect 4 times as many photons.
I’m pretty sure that’s logical and correct but if I’m the only one who thinks this then I’m probably wrong.
Yeah I think I understand, and yeah if something has 0.25 lux on it, it should appear just as bright at any distance with in your ability to see it. I don’t think something looks dimmer the further away you get so much as it’s more likely that light pollution from other sources would make it more difficult to see. Like looking up in the sky at night in town, I can’t see as many stars as I can out in the country or camping
The question is about real world useful throw distance versus a somewhat measured/ calculated throw distance. The eyes take in light and other data. The brain receives and processes that light and other data and actually does the “seeing” as we understand it. I’m not saying that a light with no spill is necessarily more useful than a flood light. What I am saying is that the way our eyes and brain works is not the same as a measured and calculated throw. My theory is related to the big picture versus the little picture. The calculated throw of a flood light is not taking into consideration all of the fluff and reflections in the big picture that our brains need to filter. So the smaller the picture or lit up reflective objects in the field of view or field of spill, allow our eyes and brain to make better use of the total measured/ calculated throw. If you’ve ever driven a car with low beams and high beams on at the same time initially it seems like a really good thing and for a lot of situations it is. However, your ability to see out at the limits of the high beam to detect animals or other objects in the road is actually diminished because those low beams are lighting up the road and sides of the road right up close in front of you. The extra light diminishes the useful throw.
IMO 2 things are not quite right with above thinking.
One is that measured 0.25 lux has nothing to do with photons reflected, but only with received by the meter.
Second one is related to reflection as well - how much light goes back to your eyes depends a lot on surface you’re illuminating and its shape and can vary from almost zero to way more than expected from hemisphere pattern.
But we’re still missing most important point IMO - how eye adaptation is affected by light spill, illuminating objects nearby, forcing pupil of your eye to close and messing up with night vision.
Even ideally repeatable conditions for testing and best formulas considering distance and logarithmic characteristic of light perception won’t tell you what effects to expect, if you won’t consider or can’t compare light spill of different lights.
I really dig that clean look and added lightness.
Is it available?
So nice, I love collaborations like this. Are you selling these with pressure switches of red/green lenses. I think I need a couple of these, they look really nice. Does the L21a/b have a larger diameter reflector than the M21A? Good stuff kiwi, the field’n’game comnunity in NZ would love them. You guys had good gun laws up until that stupid Aussie gave Jacinta justification to ‘make things safer’.