Laser and night vision - dumb question

[BigDuncs]

Since my idea of a laser is a narrow beam of light, how do they seem to be so great for aiding NV kit when surely what you would want is a wide beam of "radiation" to illuminate the darkness?

And I have this funny feeling that I will be sorry that I asked this question with the anticipated answer being so obvious.

[Marko]

Since my idea of a laser is a narrow beam of light, how do they seem to be so great for aiding NV kit when surely what you would want is a wide beam of "radiation" to illuminate the darkness?

And I have this funny feeling that I will be sorry that I asked this question with the anticipated answer being so obvious.

Don't be sorry mate, I have always wanted to know but did not want to let these gurus know how hopeless I am...oh bugger.

Marko

PS Cheers for asking!

[cliveward]

Hi Guys,

A laser illuminator when used with night vision will be in the near infra red range and unlike LED illuminators or filtered lamps, emits all it's power as one wavelength of light, rather than a range so it is more efficient for the power rating.

The illuminator will consist of a laser diode behind a focusing lens, the lens in the case of an illuminator will unfocus or diffuse the beam to make it much wider, most are adjustable to set the beam divergance to suit your scope's field of view.

Also as it's laser light, there is no leakage or bleed aroud the edge of the beam so again it is more efficient for it's power.


Cheers





Clive

[Baldie]

Since my idea of a laser is a narrow beam of light, how do they seem to be so great for aiding NV kit when surely what you would want is a wide beam of "radiation" to illuminate the darkness?

And I have this funny feeling that I will be sorry that I asked this question with the anticipated answer being so obvious.



LED illuminators or lamps with IR filters, don't illuminate great distances, lasers do. The reason you'd double the cost of your illumination, is the need to light up objects that are more distant.

Think about how this might relate to dayscopes.

A x4 mag scope, has a much wider 'field of view' than say a x20 mag scope. You might use a x4 scope up to (say) 50 yards, a x20 scope at 100 yards.

For a 50 yard target, you would use an LED illuminator that might give you enough light for the job, both in terms of distance and spread. At 100 yards, the light would probably be too diffuse (spread too widely) to be of use. So you'd use a laser, assuming you could accomodate the cost.

Lasers have adjusters on them to spread the beam, so they might be usable with a x4 or x6 mag scope. We recommend lasers, because the system we promote (the add on system) allows you to use ANY mag of scope you want. I sold a Viper 6-24 scope 2 weeks ago, with the owner shooting at targets out to 150 yards. [NOT with an airgun, with FAC grade equipment. These were safe shots to take too BTW.]

Currently, this sort of range isn't possible with LED lights, though I have a development one on its way to me. Sadly, not much cheaper than a laser. :(

...

[BigDuncs]

Thanks guys - but I guess my next question would be surely even at 100yds using an LED light there would be sufficient light for the image intensifier to use - but I suppose that the greater intensity at short range could wash this out ie the contrast would be too much?!

[Baldie]

Thanks guys - but I guess my next question would be surely even at 100yds using an LED light there would be sufficient light for the image intensifier to use - but I suppose that the greater intensity at short range could wash this out ie the contrast would be too much?!


Enough with Gen II+ perhaps.


As I advised before, a 100mw LED IR illuminator is good for 50 yards with Gen I. Longer with Gen II+.

You have to bear in mind several factors. Gen I tends to be low mag (2.5 - 4) and isn't that sensitive. Gen II+ comes in 4 - 6 mag, and offers the potential for a passive system in moonlight as the tube is much more sensitive. Image quality [resolution and appearance] is much better with Gen II+.

When you add these things together, you'll start to appreciate how the LED illuminator can be much more effective with a different scopes. But you may well be talking about a purchase price difference of £500 for Gen I and £1500/£2000 for Gen II+.

Lasers as indicated before, provide usable illumination at 100 yards, even with Gen I equipment. Lets say you buy a £500 Gen I NV system, and add a £200 laser illuminator. For £700 you get to use NV out to 100 yards. [There are other issues to consider like safety and suitable calibres of rifle at this sort of range, but these aspects are discussed elsewhere.] This combination [Gen I + Laser] cost less than half the price of a Gen II+ system. You begin to see the real benefits of high power illuminators.

[I honestly believe the Gen I add-on system will out perform a dedicated Gen II+ system at 100-150 yards, and will take up any challenge to test this belief.]

At close ranges, these high power illuminators need to be either diffused by de-focussing the beam, or switching down the power. Too much light will reduce the life potential of the NV tube, so is best avoided. If a high powered illuminator is being used at close ranges, I would have to question the wisdom of doing this. Screen burn is a one way trip, and can't be repaired.

...

[BigDuncs]

Thanks Baldie - very clear.

[cliveward]

Geoffrey,

Thanks for cheering me up with this little nugget:

"[I honestly believe the Gen I add-on system will out perform a dedicated Gen II+ system at 100-150 yards, and will take up any challenge to test this belief.]"

This begs the obvious question...what is your criteria for performance? :D


Cheers





Clive

[Baldie]

Thanks Baldie - very clear.


Goodo. :)

I had been starting to think I'd learned another language. ;) :D


Been getting someone practically stalking me on the forum, now resolved by adding a second person to my ignore list. :D :D

I expect to get much more done over the next few days. ;)

[cliveward]

Goodo. :)

I had been starting to think I'd learned another language. ;) :D


Been getting someone practically stalking me on the forum, now resolved by adding a second person to my ignore list. :D :D

I expect to get much more done over the next few days. ;)

Geoffrey,

So is that you'll take up any challenge...except mine then? :p :D


Cheers





Clive

[Baldie]

Geoffrey,

So is that you'll take up any challenge...except mine then? :p :D


Cheers


Clive


Hi Clive, completely missed this.


Yep, take up your challenge any time you like.


:cool: :cool: :cool:

[smiley1]

Do the lasers have a visible output of light to the prey ( like the red glow that comes from the led illuminators) or are they of such a wavelength that they do not show up to the prey. I assume that if they can be used for gen1 stuff then some glow from the emitter will still be visible.
Gary.

[Baldie]

Do the lasers have a visible output of light to the prey ( like the red glow that comes from the led illuminators) or are they of such a wavelength that they do not show up to the prey. I assume that if they can be used for gen1 stuff then some glow from the emitter will still be visible.
Gary.


Good question.

The emitter is certainly visble. As a strong point of light if nothing else.

Do they (rabbits) see the wavelength well enough to detect reflected light from grass or their buddies?

Experience suggests not. However, if you are close enough to them and the laser output is not diffused, there will be a point where their eye-sight is sensitive enough to see an increase in the ambient light. At close distances, it might might look to them like a weak torch is being shone at them. Just like a torch at short distance might seem to us.

Over distance [100 yards] a weak torch (to us) does not produce enough power to see reflected light from an object it might be pointed at. The laser works the same way, except it loses less power over distance, and the Image Intensifier is able to see this much better than us or the rabbit/fox/whatever.

That's what Image Intesification is all about. ;)


All that said, I've been lining up a rabbit at 35 yards to shoot, and one at 20 yards has just hopped infront of my line of sight. Sadly, I didn't get them both. ;)

[willy]

education I have had in years, thanks guys, plan a is thwarted.:o

[smiley1]

Thanks for your answers, at present I have a couple of gen 1 units with led illuminators & the rabbits certainly pick up on the fact that the illuminators are turned on, you can see their heads come up to look at you.I have just got a ranger & the glow from the illuminator seems much more diffuse than the other 2 units I have, time will tell how this one fares.
I know you can get illuminators that emit no visible output but wasn't sure which units can make use of this, can the digital stuff?
Gary.

[Baldie]

I know you can get illuminators that emit no visible output but wasn't sure which units can make use of this, can the digital stuff?
Gary.

The only truly invisible emitter [which I guess you mean to be 'invisible to the human eye'] I have seen, was so low powered it could only be used for map reading.... :o


Thank you for posting something Gary! (my previous on this subject have had no responses :o).

1) On the animals front - I'd better leave it there. (sadly)
2) Can you? (get IR Illums. at +940nm) not yet, as far as I know. Some people are working at it, but the difficulty with US sales is the 'drag factor' here. (for some good health reasons). The military have them, of course.

How many do you want? :D

3) Most Digital or CCDs work best at these 'longer' (880+nm) wavelengths.

If we could assume grown-up, careful and considerate use by all NV 'shooters' then surely a fully covert IR source would be the ideal, I agree.

All the best, to a very intelligent fellow :D
Ian


The ideal solution is no illumination. Gen III anyone? :D :D

[smiley1]

Thanks for the responses, I don't know about the intelligent fellow bit, I am new to NV & the best way to find something out is to ask questions of more knowledgable people who have already gone through the learning/asking questions stage.Your willingness to help is much appreciated by the way:D
Obviously gen3 is the ideal, but is out of reach for a lot of people,so a lot of us will be trying to upgrade cheaper units to as near gen3 performance as possible & again with the advantages of digital systems, upgrading them to perform as well as possible is going to be something in high demand.
We do not need to be totally invisible as the rabbits tend not to shoot back yet:rolleyes: but the reason a lot of us are trying out NV is so that we are as invisible as possible to the prey,no mega output lamps giving away our position & if taken to extremes not even a red glow from an illuminator (just another form of camoflauge/concealement?) I will take any edge I can get over prey that has better senses & instincts than I do.
Again many thanks for your help, it is appreciated.
Gary.

[Baldie]

We do not need to be totally invisible as the rabbits tend not to shoot back yet:rolleyes: <maybe not where you are:D> but the reason a lot of us are trying out NV is so that we are as invisible as possible to the prey,no mega output lamps giving away our position & if taken to extremes not even a red glow from an illuminator (just another form of camoflauge/concealement?) I will take any edge I can get over prey that has better senses & instincts than I do.
Again many thanks for your help, it is appreciated.
Gary.

Night time and distance are your best tools [IMO]. Cunning and experience (fieldcraft) count too of course, but if you want to be productive, often distance is the best asset.

I understand your response about Gen III, and perhaps I ought to point out my suggestion was rather tongue-in-cheek. ;) :D


ANY illuminator source can be seen. AFAIK even the 940nm illuminators carry some visible (to us) light. Not reflected light, which will be beyond our sensitivity level, but the emitter source will be observable.

[smiley1]

Thanks again for the replies, I agree with the distance thing as the rabbits seem to allow me/the illuminator glow to get within a certain distance & then decide enough is enough & they scarper. At times they seem to be more spooked by the little red glow than full lamplight, I was wondering if they looked at the small red glow in the same way as they would see predator eyeshine?
Gary.