Incorrect throw ratings

[2100]

I do agree that the brighter the light the further you see but I think you are missing the point. The point here is that our human visual perception is very limited. Seeing and making out a form is one thing, but being able to discern details of what you see is another. We can see a huge tree at a distance of 1km but other than a huge tree standing there, can we discern more details than that? No. I am vey certain about that since my eyesight is perfect. If we could all discern minute details pass the 8km range as what you have stated, we would all be bionic men and women and there is no need for visual enhancement optics like a telescope, or binocular. Maybe you can, but I definitely can't make out fine details pass 8km as what you have said.

Bro, I am *definitely* not missing the point. The guys in the military/coast guard do use optical aids for their searchlights to ID something further, but they do ID stuff without zoom to have "a wider FOV". Actually I am somewhat into astronomy as well so i am aware what is "seeable" and what is not. Some telescopes you'd want a narrower FOV ie more magnification, and for some bigger objects like Deep Space Objects you'd want a wide FOV. Do you know that some DSOs about the size of the moon and some bigger? You actually use a bino to view. Anyway I have already edited my message up there to reflect it before I got to see your reply.

 

[2100]

Iwe would all be bionic men and women and there is no need for visual enhancement optics like a telescope, or binocular. Maybe you can, but I definitely can't make out fine details pass 8km as what you have said.

Ok, put it this way. 1st step, get enough light on the object. Eg you can illiuminate a 300m tall skyscraper with a 1kW light. You can ID that "this is a skyscraper, the building name is XXX". Perhaps you want to have that spotlight effect on the building, and you are doing an assignment where your videographer want a spotlight effect on it. (this really happened as a requirement actually, so it is not far fetched, that is why i thought of this) Second step, if you want to read the newspaper that a person is holding , you get a really really good APO telescope to do that. Coz no light = no reading of newspaper.

PS. That 8km +/- 30% is the NDP spotlights at Padang. They probably have 1 dozen of them 7-10kW suckers, and at one point they all aim at Republic Plaza and past that all in one single direction. You can easily see the cloud bottoms, even high level ones, and you can see the cloud patterns. Definitely can ID the diff between nimbostratus, CB and cirrus. BTW you can even see the rain streaming coming down and the typical fall patterns which we commonly call "sheets of rain". This is no joke. Hope those are enough examples. I live there and have a clear view of MBS/RWS both directions, and I though those were bright enough already.

 

[pjandyho]

2100. Of course. What you are saying is correct. I am not saying you are wrong. You are talking about seeing forms and huge objects whereas I am talking about making out minute details from the big object. I hope I understand you correctly. So we are both talking about different things entirely. I use my lights trekking and so on, and a huge patch of trees is a huge patch of trees. No matter how bright or how far your light throws, one could really not make out much more details than that. A building is easier to discern because we know in our mind what it is. Big search lights are made primarily for the purpose of throw in an S&R operation but I seriously doubt the rescuer would be able to discern someone who is trapped in between a couple of boulders 8km away, especially if he/she is not wearing bright colored clothing.

I think we are getting way off topic. Let's talk when we can meet?

 

[rmteo]

To answer the OP's question, I have found that where throw is quoted (per the ANSI/NEMA standard), that manufacturers' figures are mostly close (within manufacturing tolerances, etc). As I mentioned in my earlier post, throw is easy to verify. All you need is a lux meter (which you can get starting at about $20) and take a single measurement. So rather than conjecturing about these figures, if you really want to know, then get a a lux meter and see for yourself.

The situation with lumens ratings is different animal altogether. To verify that, you need expensive and calibrated equipment which the average buyer does not have access to. In any event, output ratings (such as lumens for flashlight or horsepower for automobiles) tell you little to nothing about the performance of the device. This can easily be demonstrated (you don't even need a lux meter to do this) - a 150 lumen light can be shown to be brighter (have greater throw, higher lux reading) than a 1800 lumen one.

 

[the.Mtn.Man]

Having said that, I am not discounting the fact that there are manufacturers who hyped up the numbers for the sake of marketing. High number always sell better.

Then there are the edited promo pictures showing impossibly bright beams at long distances.

 

[pjandyho]

Then there are the edited promo pictures showing impossibly bright beams at long distances.

True! Very well said! I am a professional photographer and understanding exposure is my job. I could easily grossly overexpose the beam shot on my Surefire T1A and it would look like a 700 lumen light instead of a 70 lumen one, and likewise, I could grossly underexpose a 1700 lumen Olight SR92 and it would look like a 17 lumen light. That is the reason why I never trusted output of a particular light based on beam shots.

 

[bigchelis]

I never pay attention to manufactures throw ratings because they always measure throw in distance....meters, yards, feet, ect...

I only pay attention to 1M lux ratings and then depending on the Optic, reflector, Aspheric, size, and emitter, current, I make my own assumption on what it can possibly throw in lux vs. a similar light.

 

[rmteo]

I never pay attention to manufactures throw ratings because they always measure throw in distance....meters, yards, feet, ect...

I only pay attention to 1M lux ratings and then depending on the Optic, reflector, Aspheric, size, and emitter, current, I make my own assumption on what it can possibly throw in lux vs. a similar light.

With a lux rating for a given distance (1m. in your case), you do not need to make any assumptions regarding throw (which whether you like it or not is defined as distance - meters in the case of ANSI/NEMA standard - not in units of intensity such as lux), you can just calculate it. BTW, once you have the lux reading, the other factors (such as the Optic, reflector, Aspheric, size, and emitter, current, etc.) do not matter at all - they are already factored in.

 

[pjandyho]

With a lux rating for a given distance (1m. in your case), you do not need to make any assumptions regarding throw (which whether you like it or not is defined as distance - meters in the case of ANSI/NEMA standard - not in units of intensity such as lux), you can just calculate it. BTW, once you have the lux reading, the other factors (such as the Optic, reflector, Aspheric, size, and emitter, current, etc.) do not matter at all - they are already factored in.

I am not the expert here but what rmteo said sounds logical. Isn't the lux reading supposed to be the final reading after exiting the reflector, optic or aspherics?

 

[ebow86]

As long as their's company's making flashlights there will be exaggerated claims. I think one issue is people pay way too much attention to the numbers on the products spec sheet. Forget all those numbers, figures and calculations. Don't worry if your light isn't throwing as far as the manufacturer claims, forget that it isn't outputting the exact number of lumens the maker claims, just get out there and enjoy the light for what it is. If you keep worrying about those numbers then you'll never enjoy the light.

 

[Walterk]

they are already factored in.

Only when they are measured (not a calculated guess ) by a trusted source. So, who can you trust? Not the manufacturer. (Using ANSI-rating or not.)
But you can check and compare with forum reviews and your own experiences.lovecpf

 

[the.Mtn.Man]

True! Very well said! I am a professional photographer and understanding exposure is my job. I could easily grossly overexpose the beam shot on my Surefire T1A and it would look like a 700 lumen light instead of a 70 lumen one, and likewise, I could grossly underexpose a 1700 lumen Olight SR92 and it would look like a 17 lumen light. That is the reason why I never trusted output of a particular light based on beam shots.

Though to be fair, it is very difficult to take a picture exactly as your eye sees it, but marketers rather obviously fudge their images to make lights look brighter than they really are. I remember getting a laugh from one particular ad showing a flashlight at night lighting up a canyon wall like it was high noon.

 

[pjandyho]

I remember getting a laugh from one particular ad showing a flashlight at night lighting up a canyon wall like it was high noon.

That's advertising my friend. I do exaggerate a bit when it comes to advertising shots in my work.