To newcomers to Night Vision things can seem quite daunting, with a seemingly endless amount of knowledge required and not all of it readily available. We at Tactical Imports are owners and users of Night Vision equipment and have firsthand knowledge to assist with any NVD inquiry.
Basic Terminology:
FOM –Figure of Merit –this is your Signal to Noise Ratio multiplied by your Resolution (lines per mm). This is the most basic determination of tube quality
ABC/BSP –Automatic Brightness Control/Bright Source Protection. This electronic feature automatically reduces voltages to keep the image intensifier’s brightness within optimal limits and protects the tube. This is most apparent when rapidly changing from low-light to high-light conditions; the image gets brighter and then, after a momentary delay, suddenly dims to a constant level.
Autogating –This was designed to improve ABC/BSP to be faster and to keep the best resolution and contrast at all times. Autogating reduces blooming or washout from dynamic lighting conditions while also decreasing strain on tube for increased longevity.
White Phosphor –Instead of the standard green and black display, white phosphor uses black and white. This provides a high level of contrast over standard tubes and is easier to pick out finer details, all else being equal.
Manual Gain –The ability to control the tube brightness. By increasing the tube brightness the picture will get brighter at the expense of increased noise (picture grain). On the other side being able to turn down the brightness will allow less noise to be visible. Gain is typically automatically controlled by the unit, manual gain is simply the ability to override this as the user desires.
Comparisons:
CGT vs Milspec
The difference between CGT (Commercial Grade Tube) and Milspec tubes are the size, location and number of black spots on the tube, these are common and normal parts of the manufacturing process.
Gen 2 vs Photonis vs Gen 3
Contrary to popular belief, Night Vision Generations are technology differences, not performance metrics. Companies in the United States and Russia abandoned Generation 2 technology when Generation 3 technology came out, which is why the best tubes from these countries are Generation 3. However Photonis, located in France, continued to develop Generation 2 technology to Generation 3 Levels of performance. Comparing a Photonis tube and a Gen 3 tube of the same FOM, the Photonis tube will provide less blooming in dynamic lighting conditions (ie urban environments) where the Gen 3 will provide more light amplification when in very dark conditions (ie cloud cover at night in forest)
Monocular vs Bi-Ocular Vs Binocular
Monoculars are single tube devices with a single ocular. They are compact and lightweight, however they do not provide depth perception, making moving quickly though environments with obstacles more difficult. Bi-Oculars are single tube devices with dual oculars. These are best used for static observation purposes to avoid strain on the second eye. These do not have depth perception and due to the second eye being used, provide little situational awareness and are therefore not recommended for tasks requiring movement. Binoculars are dual tube, dual ocular devices, that provide true stereoscopic night vision for best immersion and ease of use. The brain also combines both pictures received by the eyes and the user actually perceives a better picture quality then if only using a single eye for viewing. Downsides are higher cost, higher weight and loss of ambient lighting condition awareness. As you can see, not one device is better then any other the others, they are different tools for different jobs.
IR and Night Vision
Infrared is a type of light that is not visible within the visible spectrum of the human eye. It is however visible with Night Vision Devices (NVD). IR light is used to illuminate areas with low available ambient light to provide better view of dark areas. IR light is available as an IR Flashlight, IR Laser Illuminator and an IR Laser. IR Flashlights provide short range illumination, similar to how a flashlight would work. Small IR Illuminators are often found attached to NVD’s and can be used for backup purposes. IR Laser Illuminators are much more powerful from IR flashlights and can provide IR illumination over much greater distances and at a much higher intensity. IR Lasers are used as aiming devices and are very intuitive to use when attached to a firearm/airsoft gun, as looking through conventional sights can be more difficult when under night vision. IR Lasers and IR Laser Illuminators are used in what is called a Laser Aiming Module (LAM), a dedicated device that houses single or multiple functions, most often attached via Picatinny mount.
Bayonet Vs Dovetail Interface
Bayonet is standard interface when using a PVS-7, however dovetail provides a tighter fit with less slack and is recommended when given the option. Note: the Flip Up Helmet Mount and the J-Arm (when using a monocular) must match the same interface.
What do I need with my NVD?