It is common, that to make a right choice is generally not an easy task. Currently there are hundreds of different types of models of night vision devices from different manufacturers on the market. The reading of abstruse instructions with manifold technical information brings no new insights for the inexperienced buyer. From time to time the uninformed purchaser may be misled by excessive and unrealistic (not uncommonly 5 – 100 times higher) product performance figures, which are for bait advertising only.

The following information includes basic knowledge about night vision. The intention is to support the night vision interested purchaser and offer him a better knowledge in this specialty area – to make a right choice. We are also always grateful to help you with any technical questions or practical operating issues, personally.

All night vision devices (residual light intensifier) operate on a basis of multiple amplifying of available light sources at a visible and near-infrared wave range. The night vision device consists of a lens, an image intensifier tube (tube), a power source and an ocular. The available ambient light (residual light) which is emitted by the observed objects gets through the optical- lens, further through the entrance of the tube on a plate with a photosensitive layer (cathode) by what the image of the observed object is formed. This image is electrically amplified and projected in the vacuum chamber on the output side of the tubes phosphor layer (screen). The result is a greenish-yellow optical picture, which gets through the lens to the eye of the observer. Only a few high-tech tubes (ONYX™ – Technology) operate in a natural black/white modus.

BLACK/WHITE (ONYX™) is the alternative black/white night vision technology. Several studies have shown that observed happenings at night are looking more natural by using the black/white technology, instead the usual green one. The black/white technology is invented for those, who value a less eye stressing night observation. This black/white technology is more precise and clearer by transmitting information such as contrast, shapes and shadows.

Basically: the qualities of a night-vision device are determined by the tube and the optical system. Compatible with the introduced terms there are differences among the types of tubes of Generation I, Gen. II and Gen. III (with subdivisions Gen. I+ and Gen. II+). Whereby the tubes of the European production (PHOTONIS) are not entirely matching the classifications (Gen. I, I+, II, II+, III), which were introduced by the USA (ITT). Therefore this (European) production has to be considered separately, because the European developers stroke another way and developed their own advanced technologies (CommGrade 1441/1451, CommGrade ECHO, SuperGen^®, XD-4™, XR5™).

FOM, performance value of a tube

The figure of merit (FOM) is used to determine the performance of a tube. This value is easily calculated for all types of tubes from known measured values. It provides a very distinctive insight in the performance and quality of all modern types of tubes. This parameter is used by the US authorities for determining the exportability of a tube. It means that the US export of tubes with a high FOM value is regimented and limited, since this value precisely defines the military advances and the performance of the tube.

The FOM value is calculated in the following manner: S/N x lp/mm (S/N = signal to noise ratio). The FOM value is able to reach currently* a rate of 2000, by Gen. II, Gen. II+, ECHO, SuperGen^®, Gen. III, XD-4™ and XR5™. It is an extreme high value, but not the maximum (PHOTONIS is able to reach a value of 2340 with XR5™ tubes – this value is a peak currently* around all types of tubes. The purchase of this technology is only possible for a few state security institutions, which have no restrictions and posses an unlimited budget). The FOM value varies from one tube to another. Many good tubes have currently* a FOM value of app. 1600. But also tubes with a considerable lower FOM value can be of excellent quality. Thus, the FOM is only one of many other parameters. Therefore it is very important whether the tube is individually meeting the requirements and if the advisory service for the customer is designed in a fair way. Thus, tubes with a very high S/N value and a very high resolution (lp/mm) have the highest FOM value.

Some FOM value examples for PHOTONIS tubes from our range:

(* state: 2019-02-01)

Image Intensifier Tubes of
Generation I

The Generation I tubes posses a glass-vacuum chamber with a cathode photosensitivity of 120 – 250 µA/Lm, at 2850K. The light amplification of such type of tubes is between 120 – 900 times, the resolutions of pairs between 25 – 35 lp/mm (Development from the middle of the 1950s).

This type of devices that are equipped with Gen. I, you may find on the market for app. 300 EUR. A specific characteristic of the Gen. I devices is, that the reproduced image is only sharp in the middle and distorted at the borders of the observation image. Especially if diverse light sources like flashlights or illuminated windows emerge in the field of view – the whole observation image is overexposed and the observation is utterly impossible.

After their manufacturing, the tubes are classified within their Generation-categories in quality grades (A, B, C and not successful manufactured tubes with grade D). This division is reflected in the prices of the tubes. This explains why, similar devices of the same generation category of various manufacturers are offered at different prices. The division in diverse quality grades is based on photosensitivity of the cathode, resolution and clarity of the image. The little black dots should not be disturbing for the observer in the darkness, wherefore the purchaser should not criticize this characteristic. In contrast, devices with bright and permanent shining points or with a bright spot in the middle of the image are unsuitable for a good observation – please do not buy these products.

Also is not recommended to purchase low-contrast tubes with a dull and blurred image. The purchaser may understand and recognize whether the image is clear or spots loaded, but only a trained eye is able to ascertain the photosensitivity of a device – which in fact is the major criteria. The photosensitivity is tested under realistic nighttime conditions, by comparison of various devices.

Due to the low amplification, the single-stage (single-stage = 1 tube, multistage = 1, 2, 3 tubes built in a row) Gen. I devices are depending on the light intensity of the optics and on the performance of the tube. Only devices with high-quality tubes in connection with especially light sensitive optics (relative aperture not higher than F1.5) are able to ensure an optimal observation during twilight and total darkness with ¼ moonlight. At lower surrounding illumination the night vision device (image intensifier) requires an additional light source, an IR-illuminator. Very good Gen. I devices have an automatic protective function against high increase of the overall lighting level, thus this function counteracts the wearing of the tube when suddenly intense light sources appears or the device is unintentionally switched on at daylight time.

To increase the performance a number of tubes are placed in one case (multistage devices). The light amplification of a three-stage-device can be app. 20000 up to 50000 times higher. However, through this procedure strong distortions occur and the resolution on the edges of the image decreases intensely. Multistage devices are unhandy and heavy, that’s why they have been almost forced out of the market by devices of the Gen. I+ and Gen. II. Devices of the Gen. I+ and Gen. II have an obviously better performance and are only a bit more expensive then the multistage devices of the Gen. I.

Gen. I+ tubes a further development of the 1^st generation (development from the end of the 60s). In the construction of Gen. I+ tubes a fiber optics slice is placed at the input (sometimes also at the output) instead of a flat glass – thereby the resolution of the tube is increasing substantially, the shape-distortion is being reduced and the anti-dazzle function from lateral dazzling effects increased.

Such types of tubes are characterized by a light amplification of app. 1000 times, the photosensitivity of the cathode is at least 280 µA/Lm at 2850K and the resolution of the line pairs in the centre of the image is between 45 – 50 lp/mm. The difference between devices with Gen. I+ tubes and their previous model with Gen. I tubes, is a clear and pleasant picture, low self-noise and a greater observation distance – in the passive and active state (using the IR-illuminator). These Gen. I+ devices are preeminent applicable in urban areas. Additionally, by natural light (residual light) are such devices applicable up to a limit value of ¼, of the natural moonlight. The price of a Gen. I+ tube is only app. 4 up to 9 times higher than the price of a Gen. I tube.

Image Intensifier Tubes of
Generation II

The Gen. II tube differs constructional from the Gen. I+ tube due to the presence of a special electron-amplifier – microchannel plate (MCP), which is placed between the cathode and the phosphor layer (screen) (Development of the end of the 60s). In such a tube, the electrons are multiplied by a very high quality, high-class micromechanics (with 8 – 12 millions channels of only 18mm diameter effectiv area). The effort necessary to produce such a high-class tube is reflected in the price of it. By manufacturing a Gen. II, II+ tubes a Multi-Alkali cathode is exclusively used.

The Gen. II+ devices have no acceleration chamber. The tubes are characterized by a light amplification of app. 25000 up to 35000 times, the photosensitivity of the cathode is at least 500 µA/Lm at 2850K and the resolution of the line pairs in the centre of the image is between 39 – 45 lp/mm (Development of the end of the 80s). Life expectancy of Gen. II+ tubes is around app. 1000 up to 3000 hours. Due to the absence of acceleration chamber is the light amplification by Gen. II+ tubes lower then by tubes of the Gen. II. By the difference in the photosensitivity of the cathode and particularly higher sensitivity for infrared light, the Gen. II+ devices are prove to be better than the Gen. II devices by natural light (residual light). If the main task of the night-vision device is to shot photos or/and videos, it is advisable to choose a Gen. II device with a higher light amplification. All devices of the Gen. II and Gen. II+ have an automatic brightness control (ABC) for retaining the equal brightness by changing of the ambient light (residual light), as a automatic protective function by intense increase of the overall level of illumination, bright source protection (BSP) for blooming-protection of strong punctual light, as well as high image quality without distortions over the entire screen area.

Gen. II and Gen. II+ devices belong to professional night vision and are currently in the military use, because these devices are able to operate during very low ambient light (residual light) – which can be compared with a starry sky or even partly clouded starry sky.

Image Intensifier Tubes of
Generation III = ECHO, SuperGen^®, XD-4™, XR5™

Gen. III tubes differ from the Gen. II+ tubes by their construction of the cathode. Gen. III tubes have a Gallium-Arsenide cathode (GaAs) with more sensitivity for IR-light. The light amplification is around app. 30000 up to 55000 times, the photosensitivity of the cathode is around 900 – 1600 µA/Lm at 2850K and the resolution of the line pairs is 32 – 64 lp/mm (omnibus 1 and omnibus 2 where developed end of the 70s, omnibus 3 and omnibus 4 is a further development of the late 80s. Omnibus 7 is currently* the most powerful Gen. III tube with a FOM value of app. 2300). The performance of Gen. III tubes may vary, depending on type and specifications (omnibus 1 up to currently* 7 Pinnacle), by circa 300%. The life expectancy is around 10000 up to 15000 hours, which is 3 – 4 times longer than the Gen. II tubes. Devices with Gen. III tubes are operating excellent in extremely low ambient light (residual light). The observation image is saturated, sharp, with excellent contrast and recognition of also smallest details. ECHO, XD-4™ and XR5™ tubes with an AUTO-GATING function are excellent suitable for operations in urban area.

AUTO-GATING is a special control electronics solution that is able to switch the tube on and off with a very high frequency, which is imperceptible by the eye. This innovative function allows the observer to operate in bright ambient light, or even in daylight operations. By keeping the full capability and performance, this function provides an efficient wear- protection of the device. Furthermore this electronic solution eliminates the glare of the light source by maintaining the performance. Moreover, this function meets the high tactical requirements – for instance by operating under bright lighting conditions such as military operations in urban terrains which define many of today’s missions. This special control electronic solution prevents blending and shadowing by variant types of light sources or fire and helps to minimize the abrasion of the tube.

The optics

Night vision devices optics consists of a lens and an ocular. The major requirement on a lens is a high light-transmitting function of the visible and invisible range of the IR-light. This light-transmitting function is expressed with the figures of the F-numbers (relative aperture), for instance F1.0, F1.4, F2.0, F2.8, F4.0, etc. On increasing of the figure by one the lens is transmitting 2 times less light. A high relative aperture (lower figure of the F-number) is a very important factor for a night vision device, especially for night vision devices of the Gen. I and Gen. I+. The consequence of a lowering of the relative aperture until a value of F2.4 – F2.8 is that the naked eye perceives more than a night vision device of the Gen. I with a switched-on IR-illuminator.

The development and the subsequent production of optics with a low F-number F1.5 (high relative aperture) is a very difficult and expensefull task, which cannot easily be managed by any company. Obviously the high costs of development and production are increasing the final price. In the race for the uninformed customers many producers are using lenses with a 3,5 up to 5 times magnification, but a low light-transmitting for long distances. It should be noticed that also two identical devices with completely similar tubes, the device with a stronger magnification will produce a lower-quality image than a device with a lower magnification. The range in the near surrounding area (residual light area) is shorter than by using a device with a lower magnification – but with a higher light-transmitting.

This fact is especially relevant for night-riflescopes. In some cases the producing companies are using a mirror-object-lens, which is reducing the dimensions of a night vision device but has significant disadvantages – the disguising (coverage) is not ensured, due to the fact that the mirror-object-lens is mirror based and also the light-transmitting is much lower under comparable conditions.

Ocular-construktion

The construction of the ocular has no impact on the range of the night vision device, but is very significant for the observation properties. For instance, a simplification of the construction of the ocular leads inevitable to a shape-distortion of the observed object and a low resolution on the edges of the image. The oculars of some manufacturers are able to produce only a part of the whole field of view, although the tube is a major and a most valuable component of a night-vision device. It is very significant for night riflescopes, that the ocular construction has an eye distance which is not less than 40mm, to prevent injuries in the eye region from the recoil force of the weapon. The ideal eye-ocular distance of a night riflescopes should not be less than 40 – 45 mm. It is also by no means irrelevant that an eye-ocular distance of 40 – 45mm provides a much better quality of photography and video recording.

Most night vision devices have highly developed glass optics. The exceptions are inexpensive Gen. I night vision devices with plastic optics and also some civilian types of devices from leading manufacturers. Obviously the quality of devices with plastic optics is much lower than the quality of devices with solid glass optics.

IR-illuminator

Some civilian night vision devices posses a built-in IR-illuminator, which provides the opportunity to illuminate the observed object, if there is not sufficient ambient light (residual light) to perform an observation in a passive state (without IR-illuminator). IR-illuminators are produced as laser, LED (Light Emitting Diode) and special incandescent lamps. It is important to note that laser illuminators may cause eye damages and the sales are regulated in some countries by the law. LED IR-illuminators are harmless for the eye.

If the night vision device does not have a built-in IR-illuminator, it is possible to use an autonomous IR-illuminator. The most producers do not point out that the performance figures they supply are only the input power. The input power of a device is not equal to its output power. Thus, a IR-illuminator with 75mW output power radiates physically 70% more IR-light than a IR-illuminator with 75mW input power. This fact is a key factor for using a night vision device (image intensifier) in active state (with IR-illuminator).

In some night vision devices a 900nm IR-light wave range illuminators are used. Their radiated light is not visible for the human eye and for the eyes of the most wildlife species. Such devices are used by military- or police operations, to preserve the coverage.

Mechanics

A night vision device is more attractive for the customer, the smaller, lighter and the longer range it has. However, are these demands partly contradictory. A longer range, for instance, can only be achieved by using a device with a larger lens (diameter). The choice is finally left to the customer.

Particularly worth mentioning is the construction of the night riflescope. The construction has to be shock resistant at 500G, thereby the reticle should be fixed, should not shift from its initial position and has to be remaining visible under all possible circumstances. A whole series of civilian devices for hunting, which recently were placed on the market do not meet the requirements of shock resistance by using heavy calibers like .338 Lapua Magnum, .50, .416Rigby. The construction of mentioned devices often does not provide the opportunity for mounting on various types of hunting rifles. Also a miserable constructed correction-mechanism or an incorrect mounting often causes a shift of the point of impact. So there are countless characteristics and special features in the construction and application of night riflescopes, thus it seems to be impossible to briefly introduce all of them in this short description. We highly recommend you not hesitate to contact us if you have some additional questions regarding this subject. We are pleased to give you further assistance.

Observation range

The user of night vision should take into account, that the observation range and the detection of the observed object is depending on the ambient light (residual light), the density of the atmosphere and on the contrast of the observed object and its background. At elevated ambient light (residual light) in a moonlit night or by using additional light sources, the observation- and detection range increases if the background of the observed object is bright – i.e. sand, snow etc. According to that: at low ambient light (residual light), higher density of the atmosphere and a dark background (loam, logs etc.) – the observation- and detection range decreases significantly.

In the table the average observation- and detection range of a human body with a contrasty background are displayed:

Before the purchase it should be clarified, regarding values mentioned above, which generation of the devices for which nature of task should be used. With sophisticated technologies the fields of application increases, but also the purchase costs grows accordingly.

If you have any further questions please contact [email protected]. We give you a detailed and fair advice.

Night vision devices are numerous; there’s goggles, monoculars, scopes, and binoculars. Binoculars and Goggles occupy the unique role of having two lenses to view through. This enhances your field of view and depth perception. What’s the big difference between the two? That’s what we are discussing today

Overview

Night Vision Binoculars

Night vision binoculars aren’t as common as goggles, but in many situations are the superior options. Night vision binoculars can deliver a most consistent and easy to see sight picture at a relatively low cost. At least as far as night vision goes. Night vision binoculars are excellent tools to survey and observe for extended periods of time. Most are designed simply with a low magnification to save weight and size. There are night vision binoculars in almost every night vision generation.

Night Vision Goggles

Night vision goggles are the most dynamic option for night vision devices. They allow hands-free use and provide a wide sight picture for the individual user. Night vision goggles are what most people envision when they talk about night vision. Night vision goggles have two distinct eyecups that offer a wider field of view than monoculars, and greater depth perception. Like binoculars, there are goggles in most night vision generations.

Features Comparison

Magnification

Binoculars have a nice advantage when it comes to their ability to magnify an image. Night vision binoculars are nowhere near as powerful as daytime binoculars but offer anywhere from 3 to 6 power magnification. Magnification with night vision gets tricky due to limitations with the technology. Also even though they are lower powered devices night vision binoculars are often already larger than standard night vision goggles.

Night vision goggles cannot offer extra magnification due to their inherent design. Magnified goggles would be useless as goggles and simply be binoculars. Binoculars have an advantage if you need to see something at any real distance. Your range of sight is already limited due to night vision, so extra magnification can only help.

With a target at an extended range, a pair of goggles may reveal a moving blob of greenish light, but a set of night vision binoculars will allow you to tell if that green blob is a stray dog or a suspicious person.

Clarity

Clarity is more about the generation, the quality of materials and manufacturers of the night vision goggles or night vision binoculars. One is not more intrinsically clearer than another just due to their different designs. This category is a clear tie and cannot be determined without comparing “like” with “like” and allowing the decision to be made on individual product levels.

Night Time Movements

Movements with either system will be easier than movements without. Night vision allows you to see things right in front of you, like holes, large brush, and other potential hazards. Night vision goggles are vastly superior for moving at night, and allow you to safely see where you’re going. Goggles also attach to hands-free systems that allow you to carry extra gear, and better maintain your balance as your tricky terrain, jump across small bodies of water, or if you need to climb. Binoculars do allow you to scout potential routes and identify hazards but are weak at allowing you to see what’s directly in front of you.

Uses and Applications

Surveillance and Observation

When it comes to simply observing an area for an extended period for any reason, binoculars are the better choice. They allow you to watch an area from a distance and makes seeing the details of that area easier. Binoculars offer a better sight picture than googles when observing a large area, with the ability to traverse to different distances with ease.

Binoculars allow you to also watch for more concealed positions compared to goggles which may force you to be closer than you want to the area you are observing. Regardless of the reason, you are watching an area a set of binoculars is easier to use than a set of goggles. Be it observing animals, or guarding a post.

Hunting

Hunting at night is a controversial and occasionally illegal venture. Always ensure you are within your state’s hunting laws. However, with that said, night vision goggles do allow you to use and carry a firearm. The hands-free nature of night vision goggles makes them much easier to use when hunting. Night vision goggles, when paired with an IR laser on a firearm, is also an accurate way to engage your game of choice. Night vision binoculars would make spotting and watching animals easier, but they would make it more difficult to shoot them.

Tactical

Off the bat, it’s very easy to assume goggles are the best tactical choice. They make carrying a weapon and moving possible. However, you have to examine the tactical situation. In a dynamic and flowing situation like an airsoft CQB match, a set of goggles is the superior choice. It allows easy movement, easy shooting, and a hand’s free experience.

However, on the other side of the tactical hand, not all situations are fast moving and dynamic. A police officer surveilling an objective is way better suited with a pair of binoculars that allow him to park a good ways away.

How to Choose?

How to determine the two will be easy. Look at the needs you have and identify which product works well for you. At the end of the day, it’s going to boil down to the objective at hand and what you’ll be doing.

Taking Care of your NVG

How should you use a Night Vision Device without destroying it? People are overly cautious and don?t get the full potential out of their device. After all, for many, buying a NVD, is investing in a NVD. And when you invest you want a return. That return can be maximized by knowing the limits of the device. Note: This ?How to? is going to apply to military grade Gen 2+ and Gen 3 Devices such as the PVS-14 or DTNVG.

You can basically divide it in to 3 categories: Use, Maintenance and Storage

So let’s start with how to use your device properly.

First of all, don?t turn it on during daylight, meaning direct or indirect sunlight. Without a pinhole cap (rubber protection cap with a small pinhole), turning on your night vision device during daytime is going to significantly decrease the lifetime of your image intensifier tube installed in your device. When exposed to direct sunlight, permanent damage can occur. Note that this only applies when your device is turned on. When its turned off, you can let your device sit in direct sunlight exposure without the objective cap for as long as you want to, noting is going to happen.

Rule of thumb is as soon as the sun sets you are ready to go. Autogated tubes are able to handle even more light. So if you are going to mostly use your device in well-lit urban environments, autogated tubes are highly recommended. Not only does it preserve the tubes lifetime when used in highlight environments, but also increases resolution. Non-autogated tubes suffer a slight resolution loss under highlight conditions such as well-lit urban areas.

Avoid direct exposure to bright light-sources, such as car lights, lasers, explosions, fires?
If you do happen to get exposed, simply turning the device away out of exposure, like a reflex, is going to keep it safe during its entire lifespan. Very short exposure times are by far not as dangerous as long ones.

Make sure you get that ocular diopter focus right, many people seem to struggle with that. If you don?t get it correctly focused, it is going to be like wearing a strangers glasses. To get a good focus, its good to look for a small light source far in the distance, I always use the stars. Then you adjust your objective lens on that light source. After that, go back to your ocular lens and turn it all the way counterclockwise, the image should now be extremely blurry. Then slowly turn clockwise until the light source is perfectly in focus again, immediately stop there! Now it’s well adjusted to your eyes.

Use your device when it’s raining, they are waterproof! Rain is no excuse to not use your NVD. You don?t have to handle it like a raw egg, the fiber filled nylon plastic is extremely robust, just don?t forcefully smash it on a concrete ground and you should be fine.

Now, let’s move to the basic maintenance.

Keep your lenses clean! Both objective and ocular. Use a Q-tip to get rid of any dirt or fingerprints.
Don?t use cloth or even your shirt, that is going to scratch and damage the anti-reflective coating on your lenses. Use a brush to get rid of any dirt on the housing, you can also use water. Don?t open your device! It’s filled with nitrogen gas to prevent corrosion and internal fogging on the lenses. It preserves the electronics by preventing oxidation. The military usually refills its devices every 6 months with Nitrogen, that is not really needed for civilian users.

Storage

Delivery Time and Manufacturing Process for Night Vision, Thermal Imaging Scope

Most of our manufacturers do not keep products like Night Vision, Thermal Imaging Scope assembled on the shelf. Night Vision tubes are kept separate from the body of the unit. When the order is placed, the manufacturer starts the order processing and assembly process which includes the following:

• Order processing - we collect all the necessary information including address and phone numbers. We also make sure that our customer ordered the correct product for their needs and that the product can be exported by Canada law to the country of destination. In some cases a signed export compliance form is required.
• QC - in this step the manufacturer will inspect all individual parts which will be used to assemble the night vision device for any defects.
• Production & Assembly - during production, all the parts are put together. Night Vision tubes in inserted into the body of the unit and all the complex electronics for the device are connected. This process takes place in a special lab called the "clean room" as even a small speckle of dust can cause undesired optical effect.
• QA - one the night vision device is assembled, it goes through a rigorous testing process to make sure it meets all the expected specifications and all parts function as expected. For this most manufacturers have a special "dark room" designed to allow testing of the units without causing incidental damage to the night vision tube by exposure to bright light.
• Packaging - this is a key process as well. In most case your night vision device will be shipped to you directly from the manufacturer but sometimes needs to be sent to us first. In either case items need to be packaged securely to avoid any kind of damage during transportation.
• Shipping - as described above items will most of the time ship from the manufacturer. For most domestic orders (unless shipping to POB or AFB) a premium shipper like Canada Post, FedEx or UPS will be used.

Only by following the above steps can we along with our manufacturers bring you - our customer - night vision/thermal imaging products of highest quality, However as you can understand the above process can take several days to complete. For example if your device fails QA, the entire process restarts. Also at QC stage a manufacturer may realize that the tube they have in stock has a defect and a replacement tube needs to be ordered. Due to the complexity of this process, it is prudent to expect 5-15 business days for production and handling of the purchased device. Keep in mind that this process is designed to guarantee your satisfaction with the night vision device of your choice. It occasionally possible to expedite the process for urgent orders but additional fees or other restrictions may apply.