Thermal / NVG

Before buying a night vision or thermal camera for rifles, it is a good idea to know the most important features of these devices and what exactly one or the other is used for. Here we will discuss the differences between thermal imaging and night vision designed for guns, which will be appreciated especially by those who are just starting out with this specific equipment or want to expand their knowledge about the most hi-tech things we can have in airsoft! 
 

What is night vision?

Night vision devices work with residual light in the environment (starlight, moonlight, ambient light, or IR). This residual light passes into the photomultiplier tube where photons are converted into electrons. The electrons are then multiplied by an electrochemical process and directed to a phosphor screen where the multiplied electrons are converted into visible light. Variants designed for firearms are installed in exactly the same way as rifle scopes. This allows us to observe targets at a great distance and be ready to shoot at the same time.

 Night vision goggles can be divided into military versions, where no external illumination is required and they are adapted for military use, and civilian versions, most often referred to as digital. Most military night vision devices are labeled as military equipment and are therefore prohibited for civilian use. Therefore, below we will describe digital night vision that is affordable, can be used not only at night but also during the day and some can be mounted on weapons.

Generations of night vision
Night vision optics have gone through several generations of development, usually referred to as generation 0, generation 1, generation 2, generation 3 and generation 4.

Generation 0 represents the various devices that were developed during the research phase of NVD before World War II. They had already been experimented with in warfare during World War II, but appeared as prototypes on small arms.

 

The 1st generation introduced passive IR illumination and are sometimes called "star" sights for obvious reasons. These devices were first used in the Vietnam War.

 

The second generation was developed in the 1970s. The main improvement of this generation was the introduction of the microchannel plate (MCP) using the S-25 photocathode. The quality of the output image and battery life improved dramatically and these devices began to be used for hunting and shooting.

 

Generation 3 brought further improvements with a gallium arsenide photocathode and an ion barrier in the MCP. The result was a device perfectly usable for tactical applications, both for firearms and for use on helmets.

 

Generation 4 is defined primarily by the removal of the ion barrier and automatic adaptation to ambient light. 

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Advantages and disadvantages of using digital night vision in airsoft

While airsoft battles most often take place during the day, nighttime events have their own charm. And that's where night vision is the perfect choice. But what are the advantages and disadvantages?
 

The advantages of digital night vision:
+ Low weight - thanks to the low weight, it is not a problem to carry the device for a long time, either in the hand for observation, on the weapon, or attached to a helmet
+ possibility of mounting on the weapon - thanks to this option we can use the NVG as a classic rifle scope during the day and at night turn on the night vision function
+ good ability to recognize details - thanks to this skill you can relatively comfortably recognize a fellow soldier from an opponent in the field

Disadvantages of digital night vision:
- price - the price of better quality devices is around 20 000 CZK and in case of purchasing an additional illuminator the price can range from 3000 CZK upwards
- Easily detectable - the most affordable variants require an illuminator to operate, which although invisible to the eye
- cannot be seen through fog, smoke or when someone is shining a light on us 

- can be detected very quickly by other NVGs

What are the technologies behind night vision?

Night vision technologies can be broadly divided into several categories, namely: image enhancement and active illumination.
 

Image enhancement 

This is a traditional technology that relies heavily on natural light sources such as moonlight or starlight. The lens receives ambient light. This light is then converted into electrons through a component of the image intensifier tube called a photocathode.
Yes, even light as tiny as starlight can amplify night vision so much...

Active illumination

In this technology, image enhancement is coupled with an active illumination source. 
The spectral band of the illuminator operates in the short-wave or near-infrared band (700 to 1000 nm), which is invisible to our eye. The design of the illuminator itself can be imagined as a classical flashlight, only the infrared light beam can be seen through night vision. Unfortunately, the illuminator also has a certain disadvantage, namely the maximum range distance (it varies up to about 300 m) and easily the user is detected by another shooter with night vision. 

What to look for when choosing a rifle scope for night vision?

Enlarge

The disadvantage of magnification is that the higher the value you set, the smaller the field of view will be. This can cause you to miss your target. Therefore, do not use unnecessarily high magnification. This magnification can be fixed or variable. The use of night vision itself is linked to magnification. 
 

Resistance

Night vision scopes are sophisticated electronic devices that tend to be less durable than standard optics. Today, most good quality NVDs have water, rain, and fog resistance. For use on firearms, you need to choose models that are made for these purposes.
 

Surveillance distance

Digital night vision devices cannot compete with traditional binoculars/spectacles when it comes to maximum sight distance. High-end night vision binoculars can work well up to about 300 meters. It also means that the price of a spotting scope will increase rapidly with its sight distance. 
 

Price

You can't get past the fact that most night vision devices are expensive. As you would expect, their prices increase with each generation. For airsoft, acquiring a night vision device is not only cheaper but also more practical compared to thermal imaging. If you are looking for an affordable device, Night Pearl products are a great choice. 
 

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Thermal cameras 

Thermal imaging cameras work on the principle of displaying the thermal radiation that all objects themselves emit. This makes them completely passive imaging devices that don't need any illumination of the objects or residual light, as is the case with night vision cameras. As a result, they can be used, for example, in fog, snowstorms or during the day.

Advantages and disadvantages of using thermal imaging in airsoft

Advantages of thermal imaging:
+ Light weight - Thermal imaging devices are relatively small and therefore relatively light.
+ the possibility of mounting on the weapon just like a collimator or optic.
+ no need for any ambient light - thermal imaging does not need any light source for its operation, this reduces the likelihood of detection by an adversary
+ fog, smoke, etc. do not affect it

Disadvantages:
- price - better quality devices are around 30 000 CZK 
- not detailed - compared to night vision, when using a thermal imaging camera you can't see who is who (you can see the outlines of figures or objects and their heat signature), so for example you can't see in dense vegetation with it.
- more complicated to shoot - to shoot the rifle version, you need to use a heat pad
- the camera must not be placed in direct heat sources such as the sun and fire, otherwise there is a risk of irreversible damage to the chip

- you cannot put any protective piece in front of lences

 

Important parameters of thermal imaging cameras

Thermosensor

The thermal sensor is the most important component when it comes to selecting a thermal imager. It is the determining factor for image quality and object detail. There are three elements to consider when selecting a thermal imaging sensor. These are resolution, NETD and frame rate.
 

Resolution

The pixel resolution of the sensor determines the clarity of the image. The higher the resolution, the more detailed the images will be. Another factor that affects the resolution is the pixel pitch. In this case, the smaller the pixel pitch, the better the resolution. 
 

NETD

Noise Equivalent Temperature Difference (NETD) is a measurement of the thermal sensitivity of the sensor. It emphasizes the smallest temperature differences observed across the thermal device, measured in millikelvin (mK). 
 

Sensing frequency

Frame rate is the rate at which the pixels on the display refresh per second. For an optimal image with minimal delay, a frame rate of 50 Hz is best.
 

Viewing distance

This figure depends on the magnification and lens size variables. The preferred detection range of thermal imaging binoculars/spyglasses is 1300 meters or more.
 

Aiming reticle and zeroing

Reticles are patterns that help the shooter aim accurately. It is ideal for a thermal imaging scope to have a choice of several different sighting warps in multiple colors.
The zeroing feature allows shooters to adjust the position of the sight cross to accommodate different distances.
 

Durability

Thermal imaging binoculars should have a minimum rating of IP67 and an operating temperature between -25 °C and 50 °C. If used on a weapon, it is essential to select a model with the highest possible resistance for large calibers. Airsoft is very specific in that there is an increased risk of damage to the device from flying pellets. Normally one would put protection (killslash or glass) in front of the lens, but here any protection would reduce or completely prevent the thermal imager from seeing. Therefore, very extra care must be taken when using it, or purchase special protective glass that also works on the thermal imaging camera.
 

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Is NVG or thermal better for airsoft?

Both thermal imaging and night vision are undoubtedly revolutionary and will completely change your gaming and shooting experience. When buying, it is important to navigate between the above features. For airsoft use, a thermal camera is often preferable. It can be used in both dark and light, it can detect the enemy well thanks to the heat trace, it can be shot well through the thermal. Night vision will again give us close-ups, but using the digital version with illumination you are quickly detectable by a second NVG, making you a relatively easy target at large events.
If you are just starting down this path, we hope we have made your task easier after reading this article.