NV -- Got One!

[C3PO_1]

Hi All,

Finally did it -- got a NV system £250 "as new" from private seller on ****. it's a Yukon NVRS Gen 1 system. For what I want it for, this makes good financial sense to me. This is not the "F" version so focus won't come down beneath 10m or so. I heard that adding a lens cap and drilling a 10mm hole in the centre is a workaround for focusing issue. How well does this work and does anyone have any comments or tips on the NVRS. Thanks in advance.

[Rabbit Sniper]

I couldn't get on with the idea of hunting with 2.5x mag. If I wasn't happy using a 2.5x hunting scope, then I definately would be happy having the same mag on generation 1 kit. In terms of rabbitting...

Having said they are devastating for close up ratting work, and my kill ratios (in terms of seeing a rat, and getting off a shot) were considerably higher.

The lense cap has an IR lens in it already, this would take my NVRS right down, however you wont be able to see as well obviously due to the filtering.

If you use it in the right situation, you can use it to a high degree of success.

[C3PO_1]

The lense cap has an IR lens in it already, this would take my NVRS right down, however you wont be able to see as well obviously due to the filtering.


Hi -- thanks for the reply, but not sure what you mean by this.

[Rabbit Sniper]

The IR filter restrict the amount of light that gets through, in combination with the smaller aperture, your image will be darker as a result of these two factors. The 'taking right down' refers to the result of restricting the field of view, which mean you can get a clearer picture at a lower range.

[C3PO_1]

The IR filter restrict the amount of light that gets through, in combination with the smaller aperture, your image will be darker as a result of these two factors. The 'taking right down' refers to the result of restricting the field of view, which mean you can get a clearer picture at a lower range.


Ah thanks -- I understand now. Of course the IR filter is to ensure that you don't burn the tube when using in daylight. The pinhole still isn't enough to restrict the amount of light hitting the tube.

I'll try to get a set of flip up scope covers and drill a 10mm hole in there. What do you think?

[Baldie]

A major problem with any Gen I NV is getting enough light into the tube. If It doesn't get enough light, it'll produce a lot of 'noise'. You'll recognise this as 'snow' when you look at the image screen. [Power up the unit with the lense cover on in complete darkness.]

Reducing the effective size of the objective lens will increase the depth of focus, but at the cost of light getting to the tube. [In photographic terms, it may turn an f2.8 lens into an f8 or f16 lense.] The only way to make up for this, is to increase the initial [illuminator] light levels. This means either additional bulk (one of the more powerful 'lamps' with IR filter) or a laser. [Not usually cheap.]

The NVRS-F was produced specifically to make the scope effective at short ranges.



While I (obviously) have a vested interest in evangelising about an 'add-on' solution, this would have been a reasonable alternative, if £70 dearer. [£320 delivered, but comes with 12 month warranty.] The Gen I 'add-on' system comes with an on-board illumintor which is good to 20 yards or so, and will allow close focussing to the same place your dayscope with focus to.

Dedicated systems tend to be mounted a little higher than normal dayscopes, and may produce parallax problems with short range targets. At 20 yards, I don't imagine there would be a problem with x2.5 mag though.


To test the system with a 10mm 'aperture', try using card? All but free, it will give you a 'test' result and do no damage to your system or anything else you might choose to buy later. Your illuminator is going to be the key to success/failure of the project.;)

HTH. :)

[C3PO_1]

Hi Baldie -- thanks for the reply and advice. Good point about the card. I am banking on fixing my IR-filtered Deben Mini Pro lamp onto the top of the NVRS using a £29.99 attachment to give the illumination a big boost. Failing that, I'll go the laser route.

[Baldie]

Hi Baldie -- thanks for the reply and advice. Good point about the card. I am banking on fixing my IR-filtered Deben Mini Pro lamp onto the top of the NVRS using a £29.99 attachment to give the illumination a big boost. Failing that, I'll go the laser route.


The width of the illumination beam from a laser may be too narrow. Actually, not "may be", it will be.

I think the lamp and filter will be the way to go if you can get your minimum focussed distance down to where you need it. Keep us informed? Sounds interesting. ;) :D

[cliveward]

C3PO_1,

Get a cheap plastic lens cap from a camera shop to fit and drill a 10mm hole in that to do your testing before then going for a flip up cover.

Due to the short ranges involved the built in IR should do the job fine and the smaller appeture will give you a more contrasty image. Obviously long range performance will be impeded but you can just flip the 'stepped down' cover out the way for the longer stuff.

Geoffrey,

I think your getting confused regarding dedicated systems. Parallax is an error whereby the image is not on the same focal plane as the reticle. In a correctly manufactured and set up dedicated scope there is never any parallax error as the reticle is factory set to be on the same focal plane as the output of the tube. So even if the eypiece is adjusted out of focus and the objective is out of focus the resultant blurred image will still be parallax free as it's all still on the same focal plane.


Cheers





Clive

[C3PO_1]

Thanks Clive -- I'll certainly try that. Thanks everyone for your suggestions and observations, and please keep them coming. Once the unit arrives, next weekend I'll do some tests and try too to take some pictures with different settings etc... and I'll post the results here.

BTW, are there any restrictions importing from the States Gen 2+ systems? I know they are considerably cheaper over there, roughly $=£ comparison. I know that Gen 3 cannot be exported from the States, but is Gen 2+ okay?

[Baldie]

Geoffrey,

I think your getting confused regarding dedicated systems. Parallax is an error whereby the image is not on the same focal plane as the reticle. In a correctly manufactured and set up dedicated scope there is never any parallax error as the reticle is factory set to be on the same focal plane as the output of the tube. So even if the eypiece is adjusted out of focus and the objective is out of focus the resultant blurred image will still be parallax free as it's all still on the same focal plane.

Clive


Clive,

If I understand your explanation (and I'm not sure I do) I think you are the one who doesn't understand. ;)


Parallax error here is given to mean divergence. Nearer to where the unit has been collimated [possibly 40 yards] there is an intermediate distance where the divergence is still low enough to provide a usable image. But below (say) 25/27 yards this image is unusable.

With the NVRS-F, this divergence is reduced by altering the focal point of the initial lens system. We know it as parallax correcting, but you are more accurate in telling us that it is a 'slang' term meaning parallax adjusting.

Now the cause has been fully discussed, it still leaves the conclusion, that these non-parallax adjusting scopes are less than ideal for close/near distance work. If they were, the "F" version would not exist. It's a solution to market demand....




BTW, are there any restrictions importing from the States Gen 2+ systems? I know they are considerably cheaper over there, roughly $=£ comparison. I know that Gen 3 cannot be exported from the States, but is Gen 2+ okay?


Two or three years ago there was a MASS of surplus ex-military Gen II+ tubes around that got sold for very little money. Many of these tubes found their way into kit we have seen in the UK. Some of it is very good quality given the price paid.

More recently, there has been a shift in the quality available, as these older/obsolete tubes had all but run out. The last couple I was shown were not worth the asking price.... "Scraping the bottom of the barrel" comes to mind.

I had myself bought a £1200 ATN 6900 Gen II+ unit into the country about 2 years ago. It went back as it developed a fault. No problem, except return carriage was circa £70. Not something you want to do twice. I've since found out the optics and tube had not been collimated correctly either. :o


As some here will know, I sell NV. I did a demo tonight for a Ranger that I sold, [and saw some interest in the laser adapter for it. ;) ] but the chap who made the purchase also voiced some interest in a dedicated Gen II+ unit.

When I finished showing him what an "add-on" Gen I system can do, and the distance/clarity it can do it, he went from thinking of spending £1500 on one of the units Clive and I sell, to asking to buy one of the "Airgun/rimfire" systems I have at a third of that price. [Pro "Airgun/Rimfire" for a bit more, but that includes a 30mm scope and mounts.;) ]


Most NV'ers are faced with a choice of [i] dedicated Gen I NV for £350-£600 that has typically 2.5 mag image (though two types go upto x4 mag), and also ties up a whole rifle, or [ii] a system for about £650 [includes dayscope] that provides 3-12 mag from the kit and can also be used on a multitude of other rifles.

It's a bit of a "no-brainer" for me. ;) :D


...

[cliveward]

Hi Geoffrey,

Nope I understand fine ;)

If you meant 'focus' then please don't describe it as parallax. Here is a simple definition of the term:

Parallax, or more accurately motion parallax (Greek: παραλλαγή (parallagé) = alteration) is the change of angular position of two stationary points relative to each other as seen by an observer, due to the motion of an observer. Simply put, it is the apparent shift of an object against a background due to a change in observer position.

When this term is applied to a rifle scope it always means that if the reticle is not on the same focal plane as the target, then when the observer changes his position (in our case head position behind a rifle scope), the target will appear to change position relative to the reticle. Hence parallax error.

In a night vision rifle scope there is no such error as the reticle is set to be on the same focal plane as the output of the tube which in simple terms is a screen and it's position is fixed regardless of the distance to the actual target.

If a night vision rifle scope has an adjustable objective then this is for focusing only. :D


Cheers





Clive

[Baldie]

Hi Geoffrey,

Nope I understand fine ;)

If you meant 'focus' then please don't describe it as parallax. Here is a simple definition of the term:

Parallax, or more accurately motion parallax (Greek: παραλλαγή (parallagé) = alteration) is the change of angular position of two stationary points relative to each other as seen by an observer, due to the motion of an observer. Simply put, it is the apparent shift of an object against a background due to a change in observer position.


:D :D

I look forward to you convincing perhaps 100,000+ people they misunderstand the term 'parallax correction'. ;) In the way you describe, 'parallax error' can't be corrected. [The condition is not correctable.]

From now on we must all call them Focus Correctable scopes. ;) Semantics fella, semantics.

Nice one. :cool:

[cliveward]

Hi Rob,

Don't confuse 'banter' as 'points scoring'. I even included a few smiley winkey thingies too just so nobody got the wrong idea, as did Geoffrey. :D

Regarding export of equipment from the USA you're almost right ;)

Export restrictions on everything have been tightened up in the USA and items are being added to the restricted list on a weekly basis.

A monocular with a Gen2+ tube is exportable from the USA no problem at all, unless the housing is on the restricted list, then it will require an export licence.

Dedicated rifle scopes with Gen2+ tubes are a bit of a grey area now, depending on how you read the law and most USA suppliers would sensibly apply for an export licence.

Anything Gen3 will require an export licence and as you say tubes with a particular FOM vaule are not exportable at all.

Any bare tube Gen2+ or better and under the FOM will require an export licence.

USA manufcaturers are now using European tubes in their devices due to the dwindling supply of Mil-surp tubes. As the tubes are not made in the USA, then export restrictions don't apply to this kind of product. But european tubed devices are pretty much the same price in the UK as they are in the USA.

Yep you can get some cheap Gen2+ stuff from the USA, but as you say you get what you pay for! For a little bit more you could get a device with a brand new European tube in the UK with massively better performance than a 20 year old bit of kit the US army chucked out!


Cheers





Clive

[Baldie]

Hi Rob,

Don't confuse 'banter' as 'points scoring'. I even included a few smiley winkey thingies too just so nobody got the wrong idea, as did Geoffrey. :D



Absolutely. ;) :p :D :D


Yep you can get some cheap Gen2+ stuff from the USA, but as you say you get what you pay for! For a little bit more you could get a device with a brand new European tube in the UK with massively better performance than a 20 year old bit of kit the US army chucked out!


Good advice. ;)

[Baldie]

Cool;) But while you guy's are "Bantering" away, try not to get to embroiled and forget to answer the guy's question who posted the Thread and the Question that you too both seemed to have missed will you;) :D

:) :)

You must of missed the rest of the post. ;) :D

[Baldie]

Geoffrey,

I think your getting confused regarding dedicated systems. Parallax is an error whereby the image is not on the same focal plane as the reticle. In a correctly manufactured and set up dedicated scope there is never any parallax error as the reticle is factory set to be on the same focal plane as the output of the tube. So even if the eypiece is adjusted out of focus and the objective is out of focus the resultant blurred image will still be parallax free as it's all still on the same focal plane.


Cheers

Clive


So not true..... **


Clive,

I have just had an epiphany. I reckon I know why it's called 'parallax correction'.

In a normal dayscope, you can and do focus two points to a single one, which is impossible without focussing adjustment at both ends. It also applies to NV equipment too. ;)

First, you adjust the optical system so your eye can accurately focus on the reticule. [Or on tube in NV.] Young eyes do this easily, older eyes need the dioptre adjustment to get the ret 'in focus'.

While looking at the ret or tube, your eye is focussed at the vertical plane where the ret or tube surface forms an image. [Okay so far?]

It is physically [and mechanically] impossible for your eye to focus on two planes at the same time. The solution, is to alter the focal point of the incoming (distant) image, to where the crosshairs are, or tube image is. The action on the scope [day or night] is to refocus the image, but you are re-parallaxing the second (distant) image, to that of the first image, the ret or tube imagine. This is why it's called parallax correction. (Mate. ;))

The test of this, is to move your head from side to side, and the differentiation you would normally see [in your earlier definition] will have gone. Both the crosshairs and the distance image will be seen to be moving as one. In fact it's a test to confirm the image is correctly focussed. ;)


**In conclusion, unless both images are focussed to the same point, they are not fulled parallax corrected.

If the inbound image is out of focus to the ret (or tube in NV) the image is not focussed correctly, and by default is in need of parallax correction.


I thank you. ;) :p :D :D

[cliveward]

Geoffrey,

FFS...lol...:D

All of what you say is true for a day scope but not for a night scope.

You of all people should know how an image intesifier works! There is no direct throughput of light. Thats why in some circles it's called an image converter tube. The image received onto the input window is then converted and projected onto the output window. Because there is no direct transmission of light then the output window becomes the 'target', not the actual distant target. And so long as the retcile is on the same focal plane as the output window of the tube then there is no parallax error.

Now if the objective optics are not focussed onto the input window of the tube it doesn't matter as there is still no parallax error as the internals of the tube (which is now the 'observer') do not move.

If you don't believe me...take one of your dedicated scopes out of stock, stick it on the test bench with a close target, adjust the objective until it's out of focus...now move your head around while looking through the ocular and you will see that the reticle stays at exactly the same place on the 'out of focus target'.

Let me know how you get on ;) :D


Cheers





Clive

[Baldie]

Clive, (mate),

Unless the ret is physically present (which it ain't) this test isn't pertinent.

The lens and tube are collimated (as you know 'cos we've discussed it). Once that is set, the tube only 'reports' what the focussing lens system provides.

You are trying to say, it's not possible to get an unfocussed image on the tube. Take one of your own systems out of stock and try to see an image at 20 yards. ;) I suspect, unless you use the 'Pro' unit with the PARALLAX correction system (which is what it does rather than how it does it) you will find the image blurred.

aka unfocussed.

Meaning it is focussed somewhere else.

Meaning there must be a parallax error.

:) :) :)

[cliveward]

Geoffrey,

Lol...I think we are talking about 2 different things. I'm talking about parallax and you are talking about focus ;)

You said there may be parallax problems with a dedicated scope and I'm sure you meant focus problems at short range...different things. :D

Parallax error in a rifle scope is seen as movement of the reticle in relation to the target when the shooter moves their head laterally off centre from the scope. This happens in day scopes but will never happen in a dedicated night scope, even if the target image appears completely out of focus! Try it.

I never claimed that a night scope can magically create a focused image on the tube at any range :D


Cheers





Clive

[Baldie]

:D :D

Too busy laughing to write anything useful..... ;) :D

[Marko]

I haven't got a clue about what you two are saying but finding it interesting anyway!

Cheers for that!

Mark

[BigDuncs]

May have some cash coming my way soon and have been trying to find the NV advice thread that I seem to remember was on here a few weeks ago. Anyone got a link /ref please. IIRC, it was one of the experts giving very useful tips on what to buy.