A quick guide to generations.

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  • A quick guide to generations.

    Hi all,

    One of the questions that most people struggle with, when looking at Image Intensifier based NV gear ( the green stuff ) is what "Generations" mean. So I'll write up a basic description of the basics and on generations.

    Basics: How most Night Vision gear works.

    Night Vision equipment comes in one of two forms. An Image Intensifier, or a Thermal Imager. Image intensifiers make use of available light and amplify it. Thermal imagers measure the very low levels of energy our bodies emit ( heat ) and show this as an image.

    Most night vision equipment is intensifier-based, and that uses what's known as an image tube to convert the image.

    The front of an image intensifier is a lens that focuses a picture, much like a camera does, except it focuses the image onto the image tube photocathode instead of film. This converts the photons ( light ) into electrons ( electricity ). It then uses an electrostatic field to accelerate these electrons across a vacuum and onto a phosphor screen. In this respect, it's just like an older-style CRT television, except the image comes from the photocathode, not from an electronic system.

    At this point, you could just view the image directly, and it would look like a TV screen the size of your thumbnail. So some viewing optics ( ocular ) magnifies it. In the most simple form, an ocular is a magnifying glass, so that's about it.

    Usually, both the Objective ( front end ) and Ocular ( rear end ) can be focussed, to provide a sharp image, whatever you're looking at.

    What else is there?

    Digital night vision is one of the newer forms of NV equipment around at the moment. It's basically something like your phone-camera with an Infra-Red light permanently attached and usually turned on.

    A digital image compared to a Gen1 image:


    The best commercial digital NV equipment is at roughly Gen1 performance levels. It suffers from poor resolution and narrow Field Of Vision ( how wide an angle you can see ) but it's generally pretty good compared to most Gen1 equipment.

    Generations:
    Generation 0/1

    These are not officially generations, but are commonly used to describe early technology. Generation 0 has very little amplification. You can't really see stuff with it that you can't see with your eyes, but it is more sensitive to infra-red energy than your eyes, so can be used with an infra-red torch to see things at night, without your eyes seeing the infra-red light.
    This technology was used in WW2.

    Generation 1 is a slight improvement over Gen0, in that there is slight amplification, or gain. This means an image viewed through a Gen1 viewer is about 50 to 100 times brighter than the image you can see with your eyes.

    This is useful with a full moon, or with a very bright IR spotlight, and can see as far as the spotlight can see ( or futher on full-moon nights )

    Generation1+ is supposed to have Fiber Plates to reduce distortion, but in truth, most manufacturers call their Gen1 a Gen1+ for marketting reasons. True Gen1+ tubes are usually ex-military tubes and are usually 40+ years old.

    Most Gen1's have an effective range of between 50 and 100m.

    Generation 2.

    Gen1 vs Gen2.


    This is the first "official" generation - and includes an electronic amplifier in the tube called a Microchannel Plate or MCP. Gen2 has less distortion than Gen1, and a brighter image. System gain is around 1000x to 2000x. At 2000x gain, a Gen2 device is militarily useful.

    These allow seeing at night under starlight conditions, but usally only provide slighly better vision than unaided eyes.

    They do however work extremely well under all moonlight conditions and with extra IR - and can have ranges exceeding 500m with a good IR torch.

    Gen2+ - Same as Gen2, but more sensitive to IR torches than Gen2. Also known as "extended red"

    Generation 3.

    Gen2 compared to Gen3. Gen2 is still useable, but a lot of detail is lost.


    This is much harder to get in Australia - especially if you get US made Gen3, as you'll need to arrange an end-use certificate and can't resell without permission from the US government.

    Generation 3 has an image that is similar to a very bright full moon, even under overcast starlight. It provides excellent resolution and clarity and allows good visibility at night under most conditions.

    Generation 4.

    Doesn't exist. Officially doesn't exist. Often used to describe Gen3 Filmless systems. They perform about the same as Gen3.

    Is it really that simple?

    Not really. Gen2 can reach up to Gen3 performance levels, but Gen1 pretty much sucks and has limited value due to it's very low gain. Also, very high end Gen2 ( Super Second Generation ) can match Gen3 performance levels. But generally, that's about it.

    Feel free to add questions to the bottom of the thread.

    David.

  • #2
    Interesting read

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    • #3
      Glad too see you on here Dave

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      • #4
        Great write up. I have been looking into NV equipment and have found this really helpful.

        Sounds like gen1 is a waste of time and that gen2+ may be that fine line between cost / performance.

        Any recommendations of good suppliers in Aus or willing to ship to Aus?

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          Originally posted by BlueBikesBlackGuns" post=912
          Great write up. I have been looking into NV equipment and have found this really helpful.

          Sounds like gen1 is a waste of time and that gen2+ may be that fine line between cost / performance.

          Any recommendations of good suppliers in Aus or willing to ship to Aus?
          Well, there's people like http://www.extravision.com.au/ over here, and like opticshq.com in the US. Julian at StarlightNV in the UK who supplies a lot of tubes for projects also sells to Australians. Best to shop around a bit though.

          Also, if you mention what you want your NV to do, I might be able to offer a little advice as to what might be suitable.

          And... if you're not in a hurry, consider the NV project to make your own CASCADE NV scope - they will perform at near Gen3 level for Gen1 prices, but the catch is that you have to build it yourself. Also there's another project I'm working on as a DIY solution for getting some cheap Gen2+ NV connected to a rifle. More to come on that later.

          Either way, it's important to match your NV gear to whatever use you'll be putting it to -

          Regards
          David

      • #5
        Hi David I know we have discussed these in another thread somewhat and seeing I can't get a simrad over here, is there any day night clip on units that are available in Aust and would be worth looking at as I don't want to set up a platform as a dedicated night unit also I would be using this with a fixed 10x so I believe that will eliminate a quite a few choices if not all that available here, I would like to get out to 4 or 500 meters but would live with 300 at minimum, suggestions or am I chasing stuff that is just not available here at this point in time. The other question I have is seeing the Smirad is made in Norway would that be available from sources outside the US and if so who?

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          That's a really good question. If you can handle the range reduction and active system, the new pulsar clip-on might be suitable. They are sold in Australia and are a digital clip-on.

          Here's some estimates of theoretical real-world performance levels - they are not all that accurate, but comparatively they are quite close. The calculations were based on 3% variation in brightness at the edge of human perception.


          Scope Lens FOV lp/mm Tube size Cycles Milliradians CY/MR MAX In @ 500Yd Moonlight Starlight Detect Range
          AN/PVS-5A 40 32 18 576 698.13 0.83 21.8 31.2 72.7 123.8
          AN/PVS-5C 40 45 18 810 698.13 1.16 15.5 22.2 51.7 174.0
          AN/PVS-14 40 64 18 1152 698.13 1.65 10.9 15.6 36.4 247.5
          SNS ( F4960 ) 23.6 32 25 800 411.90 1.94 9.3 13.2 30.9 291.3
          AN/PVS-4A 14 32 25 800 244.35 3.27 5.5 7.9 18.3 491.1
          PVS-24 18.6 64 18 1152 324.63 3.55 5.1 7.2 16.9 532.3
          PVS-22 15.1 64 18 1152 263.54 4.37 4.1 5.9 13.7 655.7
          PS22 12.8 64 18 1152 223.40 5.16 3.5 5.0 11.6 773.5
          PS80 12.8 64 18 1152 223.40 5.16 3.5 5.0 11.6 773.5
          D740 10.3 64 18 1152 179.77 6.41 2.8 4.0 9.4 961.2
          PVS-27 10 64 18 1152 174.53 6.60 2.7 3.9 9.1 990.1
          Raptor 4x 8.3 64 18 1152 144.86 7.95 2.3 3.2 7.5 1192.9
          D760 6.2 64 18 1152 108.21 10.65 1.7 2.4 5.6 1596.9
          Raptor 6x 5.7 64 18 1152 99.48 11.58 1.6 2.2 5.2 1737.0
          WASP8000 5.15 64 18 1152 89.88 12.82 1.4 2.0 4.7 1922.5
          Gen3+1 st / 170mm 6.06 64 25 1600 105.77 15.13 1.2 1.7 4.0 2269.1
          It's a table I made some time ago, but it provides an interesting insight into how modern tube resolution allows performance at difference ranges.

          The Inches column is theoretical best resolution, the smallest object that can be seen at that range ( eg, like a "pixel". ) - Moonlight and Starlight make allowance for loss of resolution at range due to deteriorating performance and it all assumes a very high grade image intensifier. You could further double or even quadruple the "Inches" columns for Clip-ons to make allowance for light loss through the dayscope.

          In terms of just clip-ons ( the PVS-14 is included for baseline purposes )

          Scope CY/MR MAX Zoom Max Zoom.
          PVS-14 1.67 2.3 9.1
          UNS-SR 2.92 4.0 16.0
          TANs 3.23 4.4 17.7
          PVS-24 3.55 4.9 19.5
          PVS-22 / BNS 4.38 6.0 24.0
          PVS-27 / MUNS 5.91 8.1 32.4
          CNVD-LR 7.06 9.7 38.7
          PVS-26 / UNS-LRPR 7.69 10.5 42.2
          Anyway, a PVS-27 or CNVD-LR would be best for this kind of work. The PVS-26 would seem to be the best, and perhaps would be ( matches to 10x almost perfectly ) but the F 1.85 lens means low-light performance suffers. I think, comparatively, I work out that in passive conditions, it wasn't the best solution but with some extra IR to compensate for the lenses, it would be the best you could achieve.

          Max zoom is for just increasing the magnification - no improvement in system resolution will be achieved - it's more for shot placement, but more than 4x over resolution doesn't really yield any benefit.

          As for what can you get? Well, if you have the $$$, you can probably get the above now. That's what it really comes down to - If you don't mind putting down a five figure sum on a good scope, and filling in some paperwork and paying a military importer, I imagine you can have what you like.

          Otherwise, if you just want ranged performance, a 6x scope will give good results on a dedicated system, and a dedicated rifle is cheaper than a day/night solution on a single rifle. For snipers, it makes sense to only have one rifle. Not so much for non-military shooters, where a dedicated system is optimal.

          Regards
          David

      • #6
        where would a PVS 4 or 10 or Simrad fit in the table David trying to get a datum that I have used, thanks for the info too

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          PVS-4? That's about 5th on the first table - Though keep in mind that most PVS-4's had a Gen2 tube - The 4A is Gen3, but wasn't that much better than the 4 in terms of baseline specifications, though it did have better IR sensitivity and was still an improvement.

          I don't have any information on the Simrad. If you can point me to some technical specifications, I can add it in though - ideally I need to know what size lens it has. ( focal length ) -

          David

      • #7
        My bad, missed the the 4 in there but the ones I have used were all the older ones no gen 3's or later, so they all sucked pretty much

        Ok specs for the KN203 well the ones I know are as follows tried to save them and post the doc but site wouldn't allow it so here goes;

        Detection;

        facial id ranges
        starlight low contrast 100m, starlight opt contrast 140m' 1/4 moon low 140m, 1/4 moon opt 180m

        Man detection ranges
        970m, 1350m, 1380m, 1730m parameters as above

        Vehicle
        3150m - 4070m

        System characteristics

        magnification- unity
        opt day scope mag 3-12x
        Field of view 10 degrees
        focus 25m to infinity
        Image intensifier gain 1000-50000

        Optical characteristics

        obj lens focal length 100mm
        obj lens f/number f/1.38

        Physical characteristics

        controls on/off/gain and focus
        batteries AA
        oper temp -40 f - 171 f
        submerssion 66ft for 2 hrs
        dimensions 5x7.5x8.6"
        weight 3.5lbs

        hope this sheds some light on the simrad

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          Originally posted by Brent65" post=2432
          Optical characteristics
          obj lens focal length 100mm
          obj lens f/number f/1.38
          Yes, very much so - OK, that's about the same as the PVS-27 - pretty close to it, with a good XD-4/XR5 or Gen3 more recent than Omni III.

          Regards
          David

      • #8
        David the Simrad is like 10+ yrs old in current config
        , i'd rather spend 5k ish to get one of these over 2k for a DFA75

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        • #9
          Thanks David
          I am looking at the Pulsar clip on at the moment. The DFA-75
          What are your honest thoughts on this device in terms of value for money and effectiveness at say past 100m?
          Thanks
          Gibbo

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            Originally posted by Gibbo" post=8168
            Thanks David
            I am looking at the Pulsar clip on at the moment. The DFA-75
            What are your honest thoughts on this device in terms of value for money and effectiveness at say past 100m?
            Thanks
            Gibbo
            An interesting question. Firstly, I should point out that I haven't used it, so everything I know about it is "third hand".

            The Pulsars have been pretty good so far - and are expected to outperform your average digital product. I don't know how effective the Pulsar is out past 100m, but on reputation, I'd be disappointed if it wasn't suited to shooting out to at least 200m.

            They are an "active" system, and require illumination to work effectively, so it may be apparent to anything targetted and looking directly at the beam.

            As for value for money? Personally, I think they are a little overpriced, but the lack of competitive options in the market somewhat mitigate it. Generally, they perform similar to a Gen1 with a very good illuminator, and have a very narrow FOV - though that somewhat lends itself to the application.

            Regards
            David
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