NV & Illumination

[Steyr]

This is a question directed to the NV experts on the BBS please.

I have recently been using and NV device with a friend who is using a lamp - a Deben Tracer Max Pro with a std red filter.

I have noticed that if the lamp is on a VERY low setting (barley making the bulb glow) the image in the NV tube improves dramatically.

If the two devices are run together on this basis, is the very low output from the lamp going to damage the NV.

Obviously to the human eye the light output is very low indeed but the sensitive electronics of an NV may be pushed to hard.

What are your opinions on this please.

It is tempting as the image leaps in quality and range when the lamp is used with care but............................?

Thanks

Steyr

[Recurve]

At a low voltage setting the conventional filament bulb is just starting to glow in terms of visible light, but it will probably be banging out loads of infra-red which is just what you need for your night vision unit.

Won't do your NV unit any harm, but keep an eye (hand) on the temperature of the dimmer switch for the lamp, as they can sometimes get a bit hot when driving a bulb at low settings (energy that would normally go into the bulb is being controlled/dissipated by the dimmer switch).

HTH, Phil

[Baldie]

At a low voltage setting the conventional filament bulb is just starting to glow in terms of visible light, but it will probably be banging out loads of infra-red which is just what you need for your night vision unit.

Won't do your NV unit any harm, but keep an eye (hand) on the temperature of the dimmer switch for the lamp, as they can sometimes get a bit hot when driving a bulb at low settings (energy that would normally go into the bulb is being controlled/dissipated by the dimmer switch).

HTH, Phil


I'd like to add to this ......


Your NV unit is designed to enhance available light. In doing so, it 'wears out' the function it is performing. There's another reasonably accurate thread here somewhere about tube 'life', that is pertinent.

By providing the NV tube with a wider spectrum of light than it is designed to see, it will 'wear out' it's functionality faster than it might otherwise have done. If you can see the light reflected from anything, it's the wrong sort of light. (Wrong wavelength.)

Just a note of clarity for Clive Ward who seems intent on picking up every word I write about NV.

"the wrong sort of light" is meant to mean, wrong for the job. If you can see the light reflected off of grass or the rabbit/fox, you can be sure they can. SO YOU MIGHT AS WELL BE LAMPING! :D You'll get to use better optics, and spend less money. ;)


This is simple to adjust. Get some dark blue acetate 'gels', aka lighting filters, and remove the lower end of the light spectrum. We have done this successfully with a couple of 'red' filters. Bennyblanco might be able to help with a 'gel' source. ;)

It will turn your visiable light, into invisible light. [Sometimes know as 'black light'.] But it'll be light your NV equipment CAN see, which is the whole point of using it. :rolleyes: :D

As before, filters work by blocking unwanted wavelengths, and NV'ers want quite a narrow band...... Consider where the energy (heat) from the blocked light is going to go......

...


Edit to remove potential ambiguity. :rolleyes:

[cliveward]

Bit of a common misconception this one.

Image intensifiers are actually sensitive to the full spectrum of visible light AND the near infrared region. In current Gen2 it's from 440 down to 950 nm.

This is why they work at night from moonlight (which is reflected sunlight) and starlight, and indeed other light pollution, which is all predominantly in the visible spectrum.

They are actually most sensitive to the green wavelengths, just like our own eyes.

The obvious advantage of an image intensifier being sensitive to near infrared light is that we can use an almost invisible source of added illumination when there is not sufficient ambient light to provide a useable image.

So using your lamp on a very low setting even unfiltered is not going to harm the device or show it light that it isn't designed for. :rolleyes: :D

Gen 1 doesn't go down as far into the near infrared spectrum and this is why it is working so well with your visible red filtered lamp.

You just need to ensure as always that any illumination, be it infrared, visible and indeed natural is not at too high a level for your device/tube.

With any NV system a reasonable gauge is that if the device is uncomfortable to look through or the image has poor contrast (washed out) then the illumination level is too high.


Cheers





Clive

[Baldie]

So using your lamp on a very low setting even unfiltered is not going to harm the device or show it light that it isn't designed for. :rolleyes: :D



Clive, this is getting stupid.


All NV is designed for use in 'starlight' (night time) conditions. For you to say anything else is plain idiotic.

No-one said it couldn't see all wavelengths. It's just the NV tube will last a matter of hours instead of years if you used it in daytime. :rolleyes: The exception to that might be some of the better quality (£3000+ for tube) DEP equipment.

Light entereing the tube produces a reaction, and that 'reaction sequence' has a limited life. As has been discussed before. NV 'wears out'. The more the reaction is excited, the shorter the (chronologic) life of the tube. It's that simple.

DON'T under any circumstances use the wrong light source for your NV equipment.

Unless you want to shorten its life, and generate further sales for NV resellers. :D

[cliveward]

Geoffrey,

"Clive, this is getting stupid."

I don't think giving the users of the BBS the correct information is 'stupid'. :D

"All NV is designed for use in 'starlight' (night time) conditions. For you to say anything else is plain idiotic."

Well if you thought by some stretch of the imagination that I meant during the day then yes that would be idiotic....but some might think it would aslo be idiotic to construe my post as such. What I did say was: "You just need to ensure as always that any illumination, be it infrared, visible and indeed natural is not at too high a level for your device/tube."

"No-one said it couldn't see all wavelengths."

Er sorry Geoffrey, you did. ;)

"By providing the NV tube with a wider spectrum of light than it is designed to see, it will 'wear out' it's functionality faster than it might otherwise have done. If you can see the light reflected from anything, it's the wrong sort of light. (Wrong wavelength.) "

The key to tube life, or wear if you like is to follow my advice about intensity of illumination which has nothing to do with wavelength.

"With any NV system a reasonable gauge is that if the device is uncomfortable to look through or the image has poor contrast (washed out) then the illumination level is too high."

Now cheer up you misery :D


Cheers





Clive

[Gary C]

Hmmm

Let me ask the obvious question.

How does wavelength increase wear?. Does it damage the photon / electron conversion process? I am guessing this is the case as when the photons have been converted to electrons the source is transparent to the electro chemical enhancement process, similarly re-conversion to visible light is irrelevant.

[cliveward]

Hmmm

Let me ask the obvious question.

How does wavelength increase wear?. Does it damage the photon / electron conversion process? I am guessing this is the case as when the photons have been converted to electrons the source is transparent to the electro chemical enhancement process, similarly re-conversion to visible light is irrelevant.

Hi Gary,

It doesn't. The wavelength of the photons entering the tube is irrellivant, it's the intensity of the photons which in turn dictate the intensity of the electrons hitting the phosphor output screen that dictates the wear rate of the phosphor.

In simple terms the brighter the screen, then the faster the tube is wearing.


Cheers





Clive

[Marko]

Another post which has gone way over my head but in which I want to understand.

I shall read my instruction manual carefully and do a bit of research so anything I have to contribute may be more than just fillers between interesting posts.

Many thanks for the continuing information in any case.

[Baldie]

Geoffrey,

"Clive, this is getting stupid."

I don't think giving the users of the BBS the correct information is 'stupid'. :D

Bickering is stupid. ;)

"All NV is designed for use in 'starlight' (night time) conditions. For you to say anything else is plain idiotic."

Well if you thought by some stretch of the imagination that I meant during the day then yes that would be idiotic....but some might think it would aslo be idiotic to construe my post as such. What I did say was: "You just need to ensure as always that any illumination, be it infrared, visible and indeed natural is not at too high a level for your device/tube."

Let me know the next time you see 100mw sunlight. :D

"No-one said it couldn't see all wavelengths."

Er sorry Geoffrey, you did. ;)

Your NV unit is designed to enhance available light.

You sure? ;)

The key to tube life, or wear if you like is to follow my advice about intensity of illumination which has nothing to do with wavelength.

This is true. Or would be IF the tube reacted evenly across the visible spectrum. Which as Clive has already said, it doesn't. So it does matter.

This is all a bit academic. If you can see red (any) light reflected, so can Mr Bunny and Mr Fox. Why handicap yourself looking through a x2.5 or x4 NV scope with image quality reduction that comes with it, if you are "lamping" anyway? [Duh.]

As I said, more 'exciting' means shorter tube life. Simple, eh?


"With any NV system a reasonable gauge is that if the device is uncomfortable to look through or the image has poor contrast (washed out) then the illumination level is too high."

It's possible for people to 'burn' tubes without it having even been apparent to them it's happening. So sorry, NOT a good gauge. I think it's possible to double the volume of light getting back to the tube [halving the potential life of the tube] without the user actually noticing how big the differerence was unless they had the means to measure it. I'm sure I've done it and not noticed.


Now cheer up you misery :D

Cheers

Clive


And I'll be miserable if I want. ;) :p :D


And with you telling people NV is okay to use 'standard' red filtered light (which Nightvision Supplies Ltd does NOT incidently,) how long do you think it will be before someone tries to zero one of your scopes in daylight using a red filter, because you said red light was safe? You ought to be advocating 'best practice' fella. ;)


...

[Baldie]

In simple terms the brighter the screen, then the faster the tube is wearing.




Exactly.

And because the human eye can cope (adjust) to a vast range of different illumination levels, it's practically impossible for the human eye to gauge the level.

It's also practically impossible for the human eye to gauge the colour content of visible light too.

Best light for the job is 'near invisible'. Best to get your quarry (or you might as well be lamping), and best for your scope because it's unlikely you'll have a light source that is too bright (though not completely impossible).

Stick to the best light source for the job. ;)

...

[Gary C]

Exactly.

And because the human eye can cope (adjust) to a vast range of different illumination levels, it's practically impossible for the human eye to gauge the level.

It's also practically impossible for the human eye to gauge the colour content of visible light too.

Best light for the job is 'near invisible'. Best to get your quarry (or you might as well be lamping), and best for your scope because it's unlikely you'll have a light source that is too bright (though not completely impossible).

Stick to the best light source for the job. ;)

...

But then - if the human eye can't see the correct level with visible light surely the same applies to invisible light?

Sorry if I'm being obtuse, but you still haven't established clearly how the wrong wavelength effects the sight.

a/ what part does it damage ?
b/ how does it damage it?

[cliveward]

Geoffrey,

Stop going into 'Politician Mode', nice edit btw. :D

Not picking on 'everything' you write about NV mate...just the bits that are wrong ;) :D

Lol...your post was obviously pretty much all about wavelengths of light and for the moment still contains an incorrect statement. ;)

"By providing the NV tube with a wider spectrum of light than it is designed to see, it will 'wear out' it's functionality faster than it might otherwise have done."

It's intensity not wavelength that causes the wear on the phosphor.

Anyway Steyr wanted to know if he could use his NV in conjunction with his mates red filtered lamp, while they were out lamping. The answer is yes, as long as the intensity is low enough.

Obviously as you say it would be better from a fieldcraft point of view to put a 'proper' IR filter on the lamp, but then when they wanted to take turns to shoot they would have to swap filters, etc. and then there would be the logistics of telling his mate where to point the now invisible light.

And even if the intensity is a bit higher than desirable it won't cause any noticeable problem due to the very short exposures involved, shots take seconds to take, not minutes or indeed hours which would be a problem.

The other obvious alternative as you said is to use a day scope on his own rifle, actually the best option is for his mate to buy an NV scope :D


Cheers





Clive

[Baldie]

But then - if the human eye can't see the correct level with visible light surely the same applies to invisible light??

You are right, that the human eye can't tell if the 'invisible' light is too bright. [If for no other reason, then by definition: "invisible".] But, the chances of this occurring are much smaller than with visible light. The only 'too bright' IR light I have ever seen, has been when I've pointed a completely 'live' system at the floor or tree trunk I've been standing next too.


The wavelength query has already been dealt with.

[Baldie]

Lol...your post was obviously pretty much all about wavelengths of light and for the moment still contains an incorrect statement. ;)

"By providing the NV tube with a wider spectrum of light than it is designed to see, it will 'wear out' it's functionality faster than it might otherwise have done."




Answer me a simple question.

Is NV designed for use in visible light or high band wavelength we refer to as 'starlight'. [Night Vision being a clue.;) :D ]

Let me make this quite clear. I'm not asking if it works in daylight, I'm asking is it DESIGNED to be used in daylight? The fact it responds to daylight has in some ways been designed out of higher grade DEP tubes (as you know) the fact it unfortunately works in lower band wavelengths being a handicap, not an advantage.

Generally speaking, tubes are DESIGNED to work in even higher wavebands (Gen III) than the stuff most of us oiks get to use.

[cliveward]

Geoffrey,

Mate..stop digging the hole. ;)

"Is NV designed for use in visible light or high band wavelength we refer to as 'starlight'. [Night Vision being a clue. ]"

NV is designed to use and is indeed most sensitive to visible light, which is what moonlight and starlight are, they also have a useful IR component, which is why newer generations of tubes are also now even more sensitive in these wavelengths. Simply the wider band of the spectrum the tube is sensitive to, the more useable photons there are to generate a better image.

"I'm asking is it DESIGNED to be used in daylight?"

Lol...of course not...it would be called a day scope then. :p

"The fact it responds to daylight has in some ways been designed out of higher grade DEP tubes (as you know) the fact it unfortunately works in lower band wavelengths being a handicap, not an advantage."

The latest tubes are acually designed to be useable in high light/daylight situations utilizing an auto gating power supply due to the demands of modern urban conflict.


Cheers





Clive

[Recurve]

As an aside, how inadvisable would it be to zero your NV scope in daylight with an IR filter over the lens?

[Baldie]

NV is designed to use and is indeed most sensitive to visible light,

This is complete rubbish. NV equipment is NOT designed to use visible light. Those scopes are called DAYscopes. :rolleyes: They are more sensitive to visible light, but this is an unavoidable trait, not a design requirement?

"I'm asking is it DESIGNED to be used in daylight?"

Lol...of course not...it would be called a day scope then. :p

Well done. So we are agreed NV is designed for night time use then? .... :D

"The fact it responds to daylight has in some ways been designed out of higher grade DEP tubes (as you know) the fact it unfortunately works in lower band wavelengths being a handicap, not an advantage."

The latest tubes are acually designed to be useable in high light/daylight situations utilizing an auto gating power supply due to the demands of modern urban conflict.*


Cheers

Clive


Clive, you're trying to make a 'dispute' where there isn't one.


Nightvision is DESIGNED to provide a usable image where normal (human) vision can't see. The market demand driving this is the obvious military applications.

It uses what is to humans 'invisible' light to produce an image. [aka Starlight. Or to the technically interested, wavelengths in the 800-950 nanometer range, depending on the equipment under discussion.]

Over the years, equipment has been developed to become more and more sensitive to these 'invisible' light sources, to where the systems available are really quite effective. High end equipment is now completely passive.

*Safety systems have been included that allow the occasional accident or operationally necessary use of an NV tube in daylight. These will be high end DEP equipped scopes with an XR5 tube or higher. The system used can be known as 'gated' or 'autogated'. [Though I'm sure Clive will be along in an hour or so to say I have this all wrong. :rolleyes: ] These systems are designed to prevent excess light getting to the tube.

The equipment most of us here are using, are NOT to be used in daylight.



As an aside, how inadvisable would it be to zero your NV scope in daylight with an IR filter over the lens?

If you are asking NightVision Supplies Ltd, we will give you an emphatic "No." There is no filter I'm aware of, dense enough to prevent the **200,000,000 candle power Sun from cooking (wearing out quickly) your tube in normal daylight. Some scopes are provided with covers with a hole in for zeroing in daylight.

Mindful your (mine, and almost any here) are not autogating in the way XR5's are, it may be the light source you believe is safe, may not be. Potentially you won't know for 3 months until you realise your equipment isn't as sensitive as you thought it was.... Anyway, unless the hole is perfectly aligned with the axis of the scope tube and lens system, the daylight zeroing is fraught with problems with offset from the optical error this situation produces. Or put simply, your zero will be 'off' when you use it at night.

The use of pieces of reflectant material, or box with some sort of illuminator inside, are methods recommended for zeroing in darkness.




**This is a complete guess. It's meant (only) to demonstrate the difference between using a lamp and using daylight. :rolleyes:

...

[shuckers]

I have one of the above supplied by Rob. If the intesity of the IR light source is what dictates the level of wear on the tube, what is the measurable difference between me using the on board IR or the laser that it came with. Obviously the image is a lot brighter using the laser so I assume the wear will be higher but by how much. Its quite important as I have been using the laser as a matter of course, cause I get a better image, but I could probably get away with using it less if it is going to wear out the tube significantly faster. BTW can you tell me what hours life these units have.

regards Geoff

[Baldie]

I have one of the above supplied by Rob. If the intesity of the IR light source is what dictates the level of wear on the tube, what is the measurable difference between me using the on board IR or the laser that it came with. Obviously the image is a lot brighter using the laser so I assume the wear will be higher but by how much. Its quite important as I have been using the laser as a matter of course, cause I get a better image, but I could probably get away with using it less if it is going to wear out the tube significantly faster. BTW can you tell me what hours life these units have.

regards Geoff

As a reference (from another thread) ...

Hi,

From reading a few sources the life span for Gen1, 2 and 3:

Gen 1 about 1,500 hours of continuous operation
Gen 2 about 2,500 hours of continuous operation
Gen 3 10,000+ hours of continuous operation

HTH,

Dave.


Consider the image intensifier tube as a LARGE tank of fluid. Turning on a tap below the tank releases the fluid and it runs away.

The tank is the operational life of the tube. The tap is its use. Turn it on infrequently, use just enough light to see what you need to see, and the tube will last for years.

Use it in bright light (not only opening a tap, but several) and the tube will not last anything like as long.

As a guide to the light levels you should be looking for in the tube, bright whites (will actually be seen as bright green obviously) are possibly getting on for being too bright, so should be avoided if possible. If they are unavoidable, don't let them 'linger' for long. Bright white areas are the sort of thing than can cause screen burn especially if its allowed to affect the same position in the tube.

Don't worry too much about all this. We have people with Gen I systems and lasers that have been in use together for more than 2 years. You just need to be aware that care should be taken. ;)

:) :)

[cliveward]

Geoffrey,

"This is complete rubbish. NV equipment is NOT designed to use visible light. Those scopes are called DAYscopes. They are more sensitive to visible light, but this is an unavoidable trait, not a design requirement?"

I really don't see where you're coming from here. You seem to be contradicting even yourself now.

Image intensifiers being sensitive to visible light is not an unavoidable trait! They are designed this way as most light available at night is in the visible spectrum! Look at the response curves for an S25 or GaAs photocathode and you will see that it peaks only in the visible range.

Alternatively, go out at night and have a look around. Can you see the moon? Can you see the stars? Can you see the glow of the sky from light pollution? Anything you can see with the naked eye is reflecting light in the visible spectrum....if it wasn't you wouldn't be able to see it!

There are other photocathode materials that are peaking in either the ultra violet end or near infrared end but these are used for astronomy / comms engineering and would be useless in a night vision viewer. These specialist intensifiers are readily available and see predominantly in the 'invisible' ranges...so why aren't we all using them? :rolleyes:

"It uses what is to humans 'invisible' light to produce an image. [aka Starlight. Or to the technically interested, wavelengths in the 800-950 nanometer range, depending on the equipment under discussion.]"

No it doesn't it uses visible light and some near infrared in the 350-900nm range (in the case of the very latest European designs). The response of all tubes drop off dramaticly past 800nm! So your last statement is wholly incorrect.

If you don't have the reference material to hand I can certainly e-mail it to you.


Cheers





Clive

[Baldie]

No it doesn't it uses visible light and some near infrared in the 350-900nm range (in the case of the very latest European designs). The response of all tubes drop off dramaticly past 800nm! So your last statement is wholly incorrect.



Sorry Clive, bored with your nit-picking.

Good job you aren't a spelling 'expert' or we'd all be in trouble. :D :D


Better change your company name. NV (designed to be used in daytime) scopes.com

What the tubes do, and what (we) want them to do is the difference between designed to do, and performance.

You are trying to say that NV scopes perform best in daylight, therefore they are daylight scopes. Silly, so you can carry on arguing with yourself. (Again.)

[cliveward]

I have one of the above supplied by Rob. If the intesity of the IR light source is what dictates the level of wear on the tube, what is the measurable difference between me using the on board IR or the laser that it came with. Obviously the image is a lot brighter using the laser so I assume the wear will be higher but by how much. Its quite important as I have been using the laser as a matter of course, cause I get a better image, but I could probably get away with using it less if it is going to wear out the tube significantly faster. BTW can you tell me what hours life these units have.

regards Geoff

Geoff,

Assuming you are using a relatively low sensitivity Gen1 monocular behind a day scope then you shouldn't really have a huge problem as long as you are sensible and only use the IR laser when necessary. The day scope will stop a considerable amount of light from reaching the monocular anyway, hence the need for the very powerful laser IR in the first place.

However if you are using a Gen2 monocular then there can be serious problems with using laser illumination with it behind a day scope. The Gen2 tube is far more sensitive and has a built in function called ABC or automatic brightness control to keep the brightness of the screen within tollerances. ABC works by taking an average of the screen brightness.

With the monocular behind a day scope, the outside portion of the tube is in darkness and with a laser illuminator the centre can easily become too bright ,as the ABC wont work as it can only work on the average brightness. The result is that the centre of the tube burns in and becomes dark...very quickly.

I have seen this on a number of Gen2 tubes sent for repair and there is nothing that can be done with this type of damage. The tube has to be replaced.


Cheers





Clive

[cliveward]

Sorry Clive, bored with your nit-picking.

Good job you aren't a spelling 'expert' or we'd all be in trouble. :D :D


Better change your company name. NV (designed to be used in daytime) scopes.com

What the tubes do, and what (we) want them to do is the difference between designed to do, and performance.

You are trying to say that NV scopes perform best in daylight, therefore they are daylight scopes. Silly, so you can carry on arguing with yourself. (Again.)

Geoffrey,

When you make a statement that is wholly incorrect or your understanding of how something works is wholly incorrect, and then you post this incorrect information in the public domain, taking the role of 'the oracle', when I correct you it's not nit-picking, it's giving the you and the other users of this board the correct information and indeed an education.

When somebody is trying to teach me something...I actually listen and thank them for it.

If I spent the whole time arguing black is white and mis-quoting my teacher to prove my 'incorrect' understanding, just to save face...I would never have learned anything. ;)

I remeber many years ago I made an incorrect post about the spectral sensitivity of image intensifiers, as I had misread the chart. Sid rightly picked me up on this 'using his usual very colourful language' :D . I didn't argue with him, I admitted my mistake.

I've never said image intensifiers perform best in daylight. I have correctly stated that they work best in the visible light spectrum. At night there is mainly visible light available which is why they are designed this way, like I said if you can see anything with the naked eye at night, anything at all, then there is visible light!

It's not my fault your understanding is incorrect...so don't take it out on me..gobbing off about my spelling, etc. :p


Cheers





Clive

[Baldie]

I've never said image intensifiers perform best in daylight. I have correctly stated that they work best in the visible light spectrum.

This is the same thing surely? :confused: Possibly not to you because the WORDS are different, but to the uneducated simpleton you insistant I am, they MEAN the same. :rolleyes: Visible light=daylight.

At night there is mainly visible light available* which is why they are designed this way, like I said if you can see anything with the naked eye at night, anything at all, then there is visible light!

I am happy to learn from someone who truly wants to teach me something, I've no interest in listening to, or responding to someone who insists on picking me up because I don't adhere to their 'semantic' driven view.


For example:

You have stated that NV tubes are most sensitive to green (visible) light. I have not argued this point, as it's just not pertinent. No right minded person is going to be using a green illuminator at night with their NV. But you have written 15 posts trying to argue the importance of this fact.

*Again, my definition of invisible is light in the 800-950 range where our eyes struggle or can't see. You are adamant this is the visible spectrum. Well if it is, why do we need NV? :rolleyes:

I have spent at least as much time studying response curves as you have. The point you are trying to make just isn't pertinent. Who here CARES what the photoresponse curve is like? If it's so important why hasn't anyone asked for a link.

The whole point of this thread is about NV illumination. What is and what isn't useful or usable.

These are the point I have made:

1.
If you can see light reflected off of the ground or off your target, then your targets will also see this light. In this scenario, you are not using NV in the way IT IS DESIGNED to be used, you are using NV to 'lamp' your target.

2.
Too much light will reduce the expected life of your NV tube. Since the human eye is capable of resolving an image in an extremely wide range of light 'powers' (lumens, whatever), this isn't a good gauge as to whether the light source is too strong.

3.
NV is designed to be used at night when the human eye can't or struggles to see an image. [Which Clive has agreed, in 1 out of 10 of his posts in this thread.] If there is enough light to see (enough visible light) there is no need to use NV.

4.
You can reduce the amount of visible light produced with a red lamp, by adding blue filters. I know because we've done it.

[Which of these points are in error?]

I have no need to argue/debate what is generally accepted to be invisible light. If your eye resolves images with 820nm wavelengths, the Army has a job for you somewhere warm. Me, I can't, so I use NV. *But I'll offer you a £50 bet, that if I point an LED torch emitting this wavelength light (aka 'invisible') you won't be able to tell me where that beam is at any given time.

So you see how ridiculous you seem to argue/nit pick what is meant by 'invisible'.


Discussing this issue with you is like arguing the toss with someone who says unless I spell the sun with a capital "s" it's a spelling error. It may well be, but it's not pertinent to this debate. Talking with you here is a debate on which blue is a 'proper' blue. If it looks blue, it's blue. :rolleyes:

Nor is there any point in either of us wasting our time arguing over whether I included visible or invisible light when I said NV is DESIGNED to be used at night, and DESIGNED to be used to enhance invisible light. As any fool can work out, the more covert the NV activity is for the driving market (the military) the better. This situation is also true of using NV for hunting.

The four points I've indicated about are a summary of everything I've written on this thread.

Feel free to write your own summary in a similar way. But I won't be indulging you any further over what is considered visible, and what is considered invisible. No-one here has any doubts about it, :rolleyes: nor needs a technical lecture on the difference between daylight and visible light. To me it means the same thing. I REALLY don't care you think otherwise.

...

[Gary C]

That's great Geoff, and as usual your replies are like a Beatles song. However you have still not explained, to a thicko like me, why a light of a different wavelength to visible is better for a tube given the same intensity of light?

Now, I do realise that you have abrain the size of a small planet and are a as a God to other men, so lower yourself to my level and explain in simple terms eh?

[C3PO_1]

As a complete non-expert, I would have thought intensity was the sole criteria in determining how fast a tube burns through. It's all to do with the rate at which electrons are whacking the phosphor plate. And that rate is determined by the intensity of light, regardless of wavelength.

[Baldie]

That's great Geoff, and as usual your replies are like a Beatles song. However you have still not explained, to a thicko like me, why a light of a different wavelength to visible is better for a tube given the same intensity of light?

Now, I do realise that you have abrain the size of a small planet and are a as a God to other men, so lower yourself to my level and explain in simple terms eh?

Please quote where I said this out of the context that visible light (daylight, red light, green light) is likely to be more harmful because of it's intensity, or its suitability for hunting. [Daytime hunting is called "hunting", night time hunting with visible light is called "lamping", and hunting with invisible light with NV scopes is called "hunting with NV".]

The sort of phrase I'm looking for to have quoted, will look something like:

"Purple light will damge your tube faster than green light."

"Green light won't damage your tube any faster than orange light."


As far as I'm aware I've only made the 4 points above. Anything else has been Clive exercising HIS planet busting ;) :D understanding of NV, at (what seems to be) my expense.

This is the second time you've asked about me about saying some wavelengths are more damaging than others. As far as I can remember, I haven't discussed this issue? And I've said as much 2 or 3 times? :confused:

How am I going to explain something I don't believe I've said?

...

[cliveward]

Gary,

Lol stop winding him up :D


Geoffrey,

As mentioned on another thread, it's not semantics when one person is wrong and the other right. ;)

Also I have never said I can see in the near infra red, nor that you should use night vision during the day. Thats just another case of you again for some unknown reason simply misquoting me :confused:

The only point you keep making that I have a problem with is that you state:

"It uses what is to humans 'invisible' light to produce an image. [aka Starlight. Or to the technically interested, wavelengths in the 800-950 nanometer range, depending on the equipment under discussion.]"

You are completely wrong in this assumption and you should know it if you've spent all that time studying the spectral response.

For the last time image intensifiers are designed to and indeed do work best with the visible spectrum of light.

As I have stated before...the majority of light available at night is in the visible spectrum. If it wasn't then you would not be able to see a thing with the naked eye....you would be totally blind at night. We all know, even those that have never used night vision, that even when there is apparently no moon or stalight, there is always enough ambient light to see something at night. Even if it is just your hand in front of your face, you can still see!

Now we agree that the most common sources of any light, however small, at night are the moon and the stars.

So what's moonlight? Reflected sunlight!
So what's starlight? Hmmm the sun is a star...so it's going to be pretty much sunlight again, but from a very very long way away.

And as we know we can actually see the moon and the stars at night (if it's not too cloudy :p ) then the light they emit must surely be in the visible spectrum.

This is why image intensifiers are designed to respond best to the visible wavelengths of light, because this is what is predominantly available at night, which is when we want to use it.


Cheers





Clive

[cliveward]

As a complete non-expert, I would have thought intensity was the sole criteria in determining how fast a tube burns through. It's all to do with the rate at which electrons are whacking the phosphor plate. And that rate is determined by the intensity of light, regardless of wavelength.

Yes :D

I refer you to my post #4 of this thread ;)


Cheers





Clive

[Baldie]

That's great Geoff, and as usual your replies are like a Beatles song. However you have still not explained, to a thicko like me, why a light of a different wavelength to visible is better for a tube given the same intensity of light?

Now, I do realise that you have abrain the size of a small planet and are a as a God to other men, so lower yourself to my level and explain in simple terms eh?


Ahhhhh.

By providing the NV tube with a wider spectrum of light than it is designed to see, it will 'wear out' it's functionality faster than it might otherwise have done. If you can see the light reflected from anything, it's the wrong sort of light. (Wrong wavelength.)

Just a note of clarity for Clive Ward who seems intent on picking up every word I write about NV.

"the wrong sort of light" is meant to mean, wrong for the job. If you can see the light reflected off of grass or the rabbit/fox, you can be sure they can. SO YOU MIGHT AS WELL BE LAMPING! You'll get to use better optics, and spend less money.


Does no one read what I write?


NV scopes are designed to be used at night where the available light levels are EXTREMELY low. They are not meant to be used with 1 or 2 million candle power lamps. Putting any filter across the largely warm colured light [ie Red filter] will reduce the light intensity. Putting additional filters will again reduce the light intensity further.

A 'lamp' will have precious little IR grade wavelength in it already. To detente all other wavelengths will mean the IR filtered lamp will struggle to be useful.

An example of this is the Nitesearcher lamp. Without filtration, it's good to 200 yards. With red filter perhaps a little less. [All visible light of course.] With IR filter and through an Gen I scope, light is barely visible at 50 yards. It's practically impossible to get too much light into the Gen I scope with correct filtration. MUCH easier with visible light, because the light source is stronger.

Plus, hunting with visible light isn't hunting with NV, it's lamping.:rolleyes:


Does no one get what I'm saying?

[Baldie]

This is why image intensifiers are designed to respond best to the visible wavelengths of light, because this is what is predominantly available at night, which is when we want to use it.


Cheers

Clive



I will dispute this with my last breath.

If this were true, why were Gen III tubes developed? They turn (literally) a night you could ONLY see a hand in front of your face, into green daylight. Why do they do this? [Accident? :D ] Because people want to see at night, what they couldn't see with unaided eye sight.

You understand that visible light is light we can see, don't you? :D This means not just the source (stars billions of light years away) but useful reflected light our eyes can resolve? ;) You couldn't drive your car in conditions you describe, but pilots are capable of flying helicopters with Gen III equipment.

To continuing design criteria of advanced NV tubes and digital equipment is to see further and further into to what is for humans, invisible wavelengths.

If what you say is true, NV illuminators would be emitting light we could all see. But no, they emit light that is invisible to our eye. They are designed to be covert, and NV is designed to be used in covert applications. Why is this?

You are getting seriously confused with lamping (using visible light) and using NV which is about using IIT's to provide images in an essentially extremely low light situation where minute amounts of IR light are available. :)

...

[Recurve]

Mussssstttttt ressssssisssssstttttt :D

[C3PO_1]

I will dispute this with my last breath.

If this were true, why were Gen III tubes developed? They turn (literally) a night you could ONLY see a hand in front of your face, into green daylight. Why do they do this? [Accident? :D ] Because people want to see at night, what they couldn't see with unaided eye sight.

You understand that visible light is light we can see, don't you? :D This means not just the source (stars billions of light years away) but useful reflected light our eyes can resolve? ;) You couldn't drive your car in conditions you describe, but pilots are capable of flying helicopters with Gen III equipment.

To continuing design criteria of advanced NV tubes and digital equipment is to see further and further into to what is for humans, invisible wavelengths.

If what you say is true, NV illuminators would be emitting light we could all see. But no, they emit light that is invisible to our eye. They are designed to be covert, and NV is designed to be used in covert applications. Why is this?

You are getting seriously confused with lamping (using visible light) and using NV which is about using IIT's to provide images in an essentially extremely low light situation where minute amounts of IR light are available. :)

...

Isn't the real strength of Gen 3 that they amplify to a much greater degree any photons around from the visible spectrum -- photons which are too few to register to our eyes but nevertheless photons that are still strictly part of the "visible" section of light?

[Gary C]

ps

Forgive me if you have changed your original post Geof. It's truly painful reading most of them the 1st time round. The second would be more than I could bear ;)

[Steyr]

Well..............

From a simple question ensued a heated debate.

I suppose the answer to the original question is that it is not a good idea especially long term.

My understanding of white light is that it is made up of light from both ends of the scale (visible and non visible) and is split into its component parts when viewed through a prism. The human eye can only respond to a certain band of these individual wavelengths but just because we cant see it doesnt mean it aint there in the same way out hearing only detects a relatively narrow band of sound waves.

I always understood that night time light was either direct reflection of our sun's output -typically from the moon or radiant light from stars dotted in one or two places in the infinite expanse that is space.

I also understood that the way NV worked was to pick up the electron element of light and then to magnify it so that those individual electrons become a cascade of emmissions striking a phosphur based screen creating the image we see through traditional NV tubes.

These photons would surely be from the entire band of light irrespective of which end of the band it comes from rather than being found within a specific band such as infra-red ?

I always felt that the main problem was that the device was designed to detect and react to very low levels of photons and the more light there was, the more photons would be present to be magnified to the point where the screen would be overwhelmed and be damaged either over time or due to a huge dose of full on sunlight.

As tempting as it is to perhaps use a dimmable lamp with a simple red filter, I think there is a danger of staying into the field of bombarding the unit with too much photon information so I will resist.

However, I am intrigued to ask why, when additional light is required at night to boost the image (no moon or cloud cover) it will be an illuminator from the infra-red spectrum and not another band of colour. Is it purely due to the fact that the human eye (and presumably a lot of quarry species eyesight) is unable to detect or boost the retinal image but the photons hitting the phosphur screen can ? If so - why choose infra red over ultra violet. I presume this is because UV light might be potentially more damaging ? Does an NV unit respond to UV emmissions ?

I would go on to ask what the difference is betwen Phoshpur screen NV and digital NV but I am concerned such a question will start WW3 so I will bite my lip :D

Thanks to all for the input. Very interesting:rolleyes:

[Gary C]

Ahhhhh.




Does no one read what I write?


?

We try Geoff... it's just that we usually lose the will to live before finishing..:o

[cliveward]

I will dispute this with my last breath.

Then you'll die wrong :(

If this were true, why were Gen III tubes developed? They turn (literally) a night you could ONLY see a hand in front of your face, into green daylight. Why do they do this? [Accident? :D ] Because people want to see at night, what they couldn't see with unaided eye sight.

Because they are even better at amplifying the available light...which by the way is mostly in the visible spectrum. :D

You understand that visible light is light we can see, don't you? :D This means not just the source (stars billions of light years away) but useful reflected light our eyes can resolve? ;) You couldn't drive your car in conditions you describe, but pilots are capable of flying helicopters with Gen III equipment.

Just because there may not be much light you can see with your eye, doesn't mean it isn't there. And yes what is there will be mainly in the visible spectrum. :D

To continuing design criteria of advanced NV tubes and digital equipment is to see further and further into to what is for humans, invisible wavelengths.

No it isn't. Photonis-DEP make a big thing, marketing there very top end products as having an even wider spectral response than USA Gen3...guess where? Yep in the visible spectrum. CCD based digital devices are designed to be more sensitive further into the near infrared range as they really have very poor sensitivity without lots and lots of artificial illumination...and if you are going to use a shed load of artificial illumination, better to have it in a wavelength that people can't see, otherwise the cretins taking part in Big Brother wouldn't be able to sleep with all those red glowing lamps next to the cameras when it's beddy bies time. :D

If what you say is true, NV illuminators would be emitting light we could all see. But no, they emit light that is invisible to our eye. They are designed to be covert, and NV is designed to be used in covert applications. Why is this?

Obviously if you need to use artificial illumination then it's best to use a wavelength that is less obvious to the target (see above). If not then you might as well bin the NV and use a torch or turn the lights on.

You are getting seriously confused with lamping (using visible light) and using NV which is about using IIT's to provide images in an essentially extremely low light situation where minute amounts of IR light are available. :)

Nope no confusion here. Oh and yes while there might be minute amounts of IR light available there will be an awful lot more in the visible spectrum. :D

...



Cheers





Clive

[Baldie]

Isn't the real strength of Gen 3 that they amplify to a much greater degree any photons around from the visible spectrum -- photons which are too few to register to our eyes but nevertheless photons that are still strictly part of the "visible" section of light?

Yes.

No.

Generation III is much more effective than Gen I or Gen II at intensifying any light. Yes.

Is it designed to, or does is its peak performance in the 'visible' range? No.

Current image intensifiers incorporate their predecessor's resolution with additional light amplification. The multialkali photocathode <Gen II> is replaced with a gallium arsenide photocathode; <Gen III> this extends the wavelength sensitivity of the detector into the near infrared. The moon and stars provide light in these wavelengths, which boosts the effectively available light by approximately 30%, bringing the total gain of the system to around 30,000.

From this rather concise but >> good read (http://www.physics.ohio-state.edu/~wilkins/writing/Samples/shortmed/johnmedium/index.html) <<


So there is no (further) confusion, when I talk about visible light, and invisible light, I'm not talking about light intensity. A human eye can resolve a quite amazingly low light level, and I have used a dayscope quite successfully in moonlight [0.1 lumens]. Gen III will work in light levels of 0.0001 lumens which is an overcast night sky. This light won't have an even or broad spectrum of wavelengths either. Some travel better than others.

What travels and what doesn't >> information (http://imagers.gsfc.nasa.gov/ems/gamma.html) << See first 'blue' picture.

To the question of why don't we use UV light for NV, the answer is most of it is absorbed by our atmosphere (thankfully) or we'd be blinded. [Our eyes can't tolerate high UV levels.]

Further clarity on 'visible vs invisible':

"Visible light" wavelengths >> information (http://photo.net/photo/edscott/vis00010.htm) << Note 'visible' is about done at about 720nm.

More >> information (http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html)<< on visible light. Note green light is around 510nm. YOU WILL be tested on this later. ;)


[B]Further comment:

What is the difference between (older) Gen II+, Supergens (DEP) and Gen III?

Getting past the resolution (line pairs) and noise (white speckly bits), it's how far into the 'invisible' spectrum the tube can intensify, and by what.

[Technical note: American tube manufacturers don't measure some aspects of their tubes the same way Europeans do, so 'side-by-side' comparisons on much they each intensify is not practicable.]

Have a look at a >> graph (http://www.postmaster.co.uk/fs/geoffreydavies/Public//Gen%20II%20vs%20Gen%20III.jpg) << taken from >> here (http://www.hec.afrl.af.mil/Publications/ASC91_2961.pdf)<<

You will note from this, 2 things:

1.
Older [US] Gen II tubes did 'peak' at around 500nm. [Green. ;) ] These tubes are practically obsolete and haven't been made for about 8 years or so, though continue to find buyers in the market place. [They are good value for money.]

2.
Gen III 'peaks' (provides its best performance) at 900nm. Where it is [I]designed to perform best, in the invisible (to us) wavelengths.


Have a look at the a similar chart for Supergens (generic term for DEP tubes, which are 'Super' Gen II technology tubes), as they do not have the Gallium Arsenide 'turbo' (:D ) component.

DEP tube >> graph (http://www.postmaster.co.uk/fs/geoffreydavies/Public//DEP%20tube%20sensitivity.jpg) <<

You will note that while the tubes all respond to visible light, Supergen, SHD3 and XD4 all peak at 740nm which as indicated above is the outer edge of visible light to humans, and these tubes still perform well in the 750-850nm range. Where they are designed to perform best. The XR5 tube is the most advanced shown, peaking at the 775nm range, and still outperforming the XD4s peak as high as 830nm, well outside our visible range. As it is designed to do. ;) I don't have a chart for the latest DEP tube, :o which might show a further shift toward the Gen III peak of 900nm.


ps

Forgive me if you have changed your original post Geof. It's truly painful reading most of them the 1st time round. The second would be more than I could bear ;)

Sorry it's so painful.;) :p

I didn't delete anything from the original BTW, only added the 'clarity' bit.

Well..............

From a simple question ensued a heated debate.

I suppose the answer to the original question is that it is not a good idea especially long term.

Good conclusion.

My understanding of white light is that it is made up of light from both ends of the scale (visible and non visible) and is split into its component parts when viewed through a prism. The human eye can only respond to a certain band of these individual wavelengths but just because we cant see it doesnt mean it aint there in the same way out hearing only detects a relatively narrow band of sound waves.

I always understood that night time light was either direct reflection of our sun's output -typically from the moon or radiant light from stars dotted in one or two places in the infinite expanse that is space.

I also understood that the way NV worked was to pick up the electron element of light and then to magnify it so that those individual electrons become a cascade of emmissions striking a phosphur based screen creating the image we see through traditional NV tubes.

These photons would surely be from the entire band of light irrespective of which end of the band it comes from rather than being found within a specific band such as infra-red ?

Ideally the tube wouldn't 'see' visible light at all. The reason for this is that bright visible light reduce the image quality in the short term [halo or over-brightness] and make it an opportunity for (terminal) damage if switched on for any length of time in bright daylight. As has already been mentioned, 'better' systems [read later and more expensive] have 'gating' though military applications may be manual rather than 'auto'.

I always felt that the main problem was that the device was designed to detect and react to very low levels of photons and the more light there was, the more photons would be present to be magnified to the point where the screen would be overwhelmed and be damaged either over time or due to a huge dose of full on sunlight.

As I understand it too.

As tempting as it is to perhaps use a dimmable lamp with a simple red filter, I think there is a danger of staying into the field of bombarding the unit with too much photon information so I will resist.

However, I am intrigued to ask why, when additional light is required at night to boost the image (no moon or cloud cover) it will be an illuminator from the infra-red spectrum and not another band of colour. Is it purely due to the fact that the human eye (and presumably a lot of quarry species eyesight) is unable to detect or boost the retinal image but the photons hitting the phosphur screen can ? If so - why choose infra red over ultra violet. I presume this is because UV light might be potentially more damaging ?

Yes. As above.

Does an NV unit respond to UV emmissions ?

UVA (400–315 nm) would be intensified.

I would go on to ask what the difference is betwen Phoshpur screen NV and digital NV but I am concerned such a question will start WW3 so I will bite my lip :D

Thanks to all for the input. Very interesting:rolleyes:


WWWIII ....

Digital systems don't understand the limitation of 'visible'. Nor are they difficult to make (these days). IIRC they operate in the 940/950nm range. Don't suffer from 'overbrightness' as the circuitry and logic shut the panel down to more acceptable levels. Longterm damage is harder to achieve.

The two incumbent handicaps with digital are:

1.
Resolution. At this time, digital technology doesn't provide the equivalent of 65-80 line pairs available in IIT solutions. 3 or 4 years from now, that may not be the case.

2.
Power. Digital systems need much more power than ITT tubed scopes. As anyone with a digital camera will tell you. But again, advances in Lithium Ion battery technology is set to change that too.


The End. [Thank goodness.]


P.S.

It took me circa 5 hours to research this, have a midnight snack, proof and edit the content. Consequently I missed Clives post until some time after it was made...

[Baldie]

:D :D :D

Clive ..... after this post you go on the ignore list.


To continuing design criteria of advanced NV tubes and digital equipment is to see further and further into to what is for humans, invisible wavelengths.

No it isn't. Photonis-DEP make a big thing, marketing there very top end products as having an even wider spectral response than USA Gen3...guess where? Yep in the visible spectrum.


We are talking about NV on an NV forum.

The immediate advances in digital system are in performance. Less power, and greater sensitivity. No digital NV designer is going to nominate 'daylight' sensitivity as one of the developments technicians should be spending time and money on. [Not least because it's already there.:rolleyes: ]

Check out the graphs I've put in the my last post. You will see an undeniable shift in sensitivity from DEP tubes toward Gen III's 'magic' 900nm range.

The marketing ploy that DEP is espousing, is the (marginal) use of their high spec tubes in daylight situations. This is a safety feature usable in situations of 'operational necessity', not normal working conditions. There’s no such thing as a day/night IIT. You wouldn't choose to do it for any length of time with the more tolerant digital system.

I’m not going to indulge your argumentive posts any longer. I’ve supported everything I’ve said with links to technical sites which have supported my understanding. [They are the places I learned from.]

For you to continually refute all this data, suggests you’ve either got ‘an agenda’, or suffering with another problem of some sort.

Sorry Clive, but I won't be reading any more of your posts. :(

[cliveward]

Geoffrey,

As you know, levity is often lost in the written word. All of my posts 'even when I'm disagreeing with someone' are always written in good spirit and humor, but I must confess it is very 'dry'. ;)

The actual reason for my posts is not to be contrary for the sake of it, or wind you up....well maybe just a little bit :D . The reason is to promote an interesting and in-depth discussion that the users of the board will be interested in reading, and learn something from. From the number of views our 'discussion' threads get I think we're getting somewhere with that. :D

Anyway getting back to the matter at hand...;)

If you have a look at the response curves you so excellently provided you will see that if you add up the sensitivity in the whole visible spectrum for any tube and then do the same for the near infra red spectrum you will see that there is far more sensitivity to the visible spectrum.

Then do the same with the natty graph that attempts to show what spectrum and amount of light is available at night (the dashed line). You will see that collectively there is more visible spectrum light available than near infrared.


Cheers





Clive

[Marky610]

I come on this part of the forum to try and learn something about night vision and have tried to read all these post's thinking I might learn something but they just go around in circle's getting no where. I'm bored now so in future if someone has some thing interesting to say could they start the thread or reply with the word interesting then I will catch it with a search and save myself reading all this dribble. :rolleyes:

[Carlitobrigante]

Marky,

I think the point of this thread (and this whole new forum) is free advertising for some vested interests (with a little ego-tripping thrown in).
It has nothing to do with service to BB members at all.
I will be giving it a miss in future :mad: it makes painful reading.

ATB,

Charlie.

[cliveward]

Charlie,

Sorry you feel that way. Just to put the record straight.

I know for a fact that neither Geoffrey or myself need any 'free' advertising. We pay for our advertising. Do you honestly think that spending hour upon hour posting in this section as some kind of stealth advertising is a useful and profitable endevour? I for one know what my time is worth.

Also please feel free to search for any posts where I have incorrectly suggested what to buy or impartially advised someone?

Perhaps when I was responding to the battery thread to stop someone potentially wrecking their scope or illuminator...I was secretly trying to sell them some batteries :rolleyes:

As I've mentioned on another thread, I sell literally a miniscule amount to members on this BBS, and a vast amount to 'normal' customers through 'normal' business practices.

Sorry if the banter and mickey taking has given you the wrong impression of ego-tripping.

Personally if I wanted to know about something I would be grateful of 'industry experts' giving me the BS free low down. Or perhaps you would like to get all your advice from the bloke in the pub type who got his knowledege from another bloke in the pub? Again sorry if the posts have gotten very technical...but to us it's very interesting.


Cheers





Clive

[Carlitobrigante]

Come off it Clive,

You (and others, in fairness) take every opportunity you can to peddle your wares and publicise your little side-line.
Stealth advertising? This would imply subtlety, when in fact the exact opposite is the case - every genuine query becomes a sellers gang-bang for who can shout (write) loudest.
I doubt if there is anyone on this BB that does not know this - its just the used car techniques modified.

Industry experts? If you or your sparring buddies ever meet one, perhaps you could salute them.
(I wont use the hoary old one about expert being made up of has-been and drip under pressure :) )

What this forum should be about is unbiased members reviews of night vision that they have used/bought, not continuous bombardment by a few individuals with an agenda of selling their wares.

Soviet Bazaar are sadly missed, the King is dead and there is no heirs to the throne here:rolleyes:

End-of as far as Im concerned, though I do not believe in ignore lists.

ATB,

Charlie.

[Recurve]

Well I've become embroiled in debate with Clive and Geoff, and for the record have never felt the need to rush to one of their emporia to purchase 'shiny stuff', I'm much more likely to try and make something for myself (see the DIY doubler in 'My NV Setup').

I've certainly learnt stuff, and think it's a pity that your opinion of the two opponents is so jaded.

Regards, Phil

[C3PO_1]

Come off it Clive,

You (and others, in fairness) take every opportunity you can to peddle your wares and publicise your little side-line.
Stealth advertising? This would imply subtlety, when in fact the exact opposite is the case - every genuine query becomes a sellers gang-bang for who can shout (write) loudest.
I doubt if there is anyone on this BB that does not know this - its just the used car techniques modified.

Industry experts? If you or your sparring buddies ever meet one, perhaps you could salute them.
(I wont use the hoary old one about expert being made up of has-been and drip under pressure :) )

What this forum should be about is unbiased members reviews of night vision that they have used/bought, not continuous bombardment by a few individuals with an agenda of selling their wares.

Soviet Bazaar are sadly missed, the King is dead and there is no heirs to the throne here:rolleyes:

End-of as far as Im concerned, though I do not believe in ignore lists.

ATB,

Charlie.


I think in amongst the heated debate there are real nuggets of information in which I've certainly learned a great deal. So, for me at least, the debate is well worth it.

[bennyblanco]

What this forum should be about is unbiased members reviews of night vision that they have used/bought, not continuous bombardment by a few individuals with an agenda of selling their wares.

Soviet Bazaar are sadly missed, the King is dead and there is no heirs to the throne here:rolleyes:



the constant bickering is annoying and pathetic but on the other hand they can be helpful. Geoffrey, Rob and Clive (and I'm sure Garyc too, but i have not had dealings except for hft hints:) ) have all driven **** loads of miles to demo products to bbs members and the internet public (and me too). this has allowed people to see the options before spending a load on a pretty piece of junk

if this didn't happen then everyone would end up with mini ospreys because the internet is full of rave reviews by s16 shooters, imo there is very little advertising of their websites except by happy customers.


ban them all form the nv forum for a week and see what its like:D


ben

[Baldie]

I come on this part of the forum to try and learn something about night vision and have tried to read all these post's thinking I might learn something but they just go around in circle's getting no where.

10.15am post

I'm sorry some of these threads have turned into a 'willy-waving' exercise. It's less likely to happen again because I'll be ignorant to someone telling me I'm talking B/S.

The original poster asked about a situation that would be unusual; using visible light with NV. Not only does this make NV pointless ('cos you are actually lamping), but it's the wrong sort of light for the job. The right light for the job is Infra Red. This is light up in the 800-900nm wavelength which humans struggle to see reflected.

Being a quite narrow band, it's also harder to get to an 'overbrightness' situation, and the less expensive NV systems don't provide safety features for that. The results of over-brightness lead to shortened tube life or tube damage (burn).

In this thread I tried to explain in simple terms [tank+tap] how the life of an Image Intensifer Tube is limited, and how excess light levels will accelerate the end of its life.


For some reason this information (or how it was explained) was seen as an opportunity to wind me up. [Which frankly, is as hard as taking sweets from a child.;) :D ]


2:15pm post

P.S.

This thread has taken 4 hours hours to post because it's taken that long to get off the phone. There's a big gap, and a number of posts now, that weren't there before... :rolleyes: :D

So let me address them now.

I believe in 'add-on' systems, because I've used them for 2 years, and they are the dogs danglies. I do sell NV, and for me it's a full time job. I sell dedicated too.

If I mention 'traders' I tend to mention them all. I've posts with links to Clives site, and Gavins. ANYONE making remarks about me using this as a sales forum is talking ********. I will give what I hope is an unbiased view to anyone. I often get PM's about 2nd user equipment, with no financial opportunity in the conversation at all. I still respond to EVERY query. Even the one asking ME about importing NV from America. :rolleyes: :D

And while there is a link in my profile for my web site, I don't have a email address in my signature announcing I sell NV. In fact I get asked where to buy this stuff too via PM, so I'm being about as discreet as I could be.