The 5G Image Intensifier Tube: What It Changes
Exosens has released the 5G, its highest-performing image intensifier tube to date. With a minimum figure of merit of 2500 and a typical value of 2800, it sits above anything the company has previously offered.
One point worth clearing up first, because it causes confusion: the 5G is a product name, not a new generation of night vision. The established generational classification still runs Gen 1 through Gen 3. What Exosens is doing here is naming successive tube families, the same way 4G followed earlier designs.
That does not make the performance claims less significant. It just means the 5G should be compared on its numbers rather than assumed to be a generational leap by virtue of its name.
The Headline Numbers
| Specification | Value |
|---|---|
| FOM (minimum) | 2500 |
| FOM (typical) | 2800 |
| Signal-to-noise ratio | 30 minimum |
| Limiting resolution | 82 lp/mm |
| High light level resolution (200 lx) | 62 to 64 lp/mm |
| Phosphor options | P43 green or P45 white |
Exosens states the 5G delivers around 50 percent higher gain than standard intensifiers, and DRI ranges increased by up to 35 percent across all night levels.
What FOM Actually Tells You
Figure of merit is the number most often quoted when comparing tubes, and it is worth understanding what it represents.
FOM is signal-to-noise ratio multiplied by limiting resolution. Nothing more complicated than that. A tube with an SNR of 30 and a resolution of 82 lp/mm gives 2460, which is roughly where the 5G minimum sits.
The reason it is useful is that it captures the trade-off manufacturers face. It is possible to build a tube with excellent resolution and poor signal-to-noise, or the reverse. Either one produces a disappointing image in the field. Multiplying the two forces both to be good before the number gets high.
The reason it is limited is that it says nothing about halo size, gain stability over the tube’s life, or autogating behaviour under sudden light changes. Two tubes with identical FOM can behave very differently when someone switches on a torch fifty metres away.
So FOM is a reasonable first filter, not a complete picture.
Why Gain and Halo Matter More Than People Expect
The 50 percent gain increase is the specification most likely to be noticed in use.
Gain determines how much the tube amplifies incoming light. Under starlight with heavy cloud cover, where there is very little to amplify, gain is what separates a usable image from a grainy one. This is exactly the condition where night vision is most needed and where cheaper tubes fall apart.
Halo is the bright ring that forms around a point light source in the image. A large halo will wash out anything near a streetlight, a muzzle flash, or a vehicle headlight, which in a built-up environment can obscure precisely what the operator is trying to see. Exosens lists smallest halo among the 5G’s characteristics.
Neither of these appears in the FOM calculation, which is why two tubes with the same number can perform differently.
What the DRI Improvement Means
A 35 percent increase in DRI range is a substantial operational claim, so it is worth being precise about what DRI covers.
Detection is knowing something is there. Recognition is knowing what class of thing it is, such as a person versus a vehicle. Identification is knowing specifically what it is, such as whether the person is carrying a weapon.
Each stage requires more resolvable detail than the last, so identification range is always considerably shorter than detection range. When a manufacturer quotes a single range figure without specifying which stage it refers to, the number is not comparable to anything.
An improvement of 35 percent across DRI at all light levels means the operator makes each of those judgements from further away, which translates directly into reaction time.
P43 or P45: Green or White Phosphor
The 5G is available with either phosphor, and this is a genuine choice rather than a straightforward upgrade.
P43 green phosphor is the traditional option. The human eye is most sensitive to green wavelengths, which historically made it the efficient choice, and many operators trained on green find it familiar.
P45 white phosphor produces a monochrome image in grey tones rather than green. Most users report better contrast discrimination and less eye fatigue over long periods, and the image tends to feel more natural when transitioning between aided and unaided vision.
The preference is not universal. Some experienced operators pick out detail more readily in green. Where possible, evaluating both before committing to a fleet purchase is worth the effort.
Where This Sits in the Wider Market
The 5G is a tube, not a complete device. It goes into goggles, monoculars, and weapon sights built by other manufacturers, which is why the same tube family appears across products from different brands.
When comparing complete night vision devices, the tube specification is the largest single factor in image quality, but the optics, housing, weight, mounting system, and power management all determine whether the device is usable in practice. A superb tube in a poorly designed housing is still a poorly designed device.
For how image intensification works in principle, see our guide on how night vision works, and for how it compares to thermal imaging, see infrared vs thermal.
5G Tubes Now Available in the PVS-31C-4B
The 5G is available as a tube option in our PVS-31C-4B night vision goggles. This pairs the highest-performing Exosens tube with a dual-tube binocular platform, which means the gain and DRI improvements apply across both channels rather than a single eye. For units already specifying the PVS-31C-4B, it is a tube-level upgrade within a familiar housing, mount, and power system rather than a new platform to qualify. Contact our team to discuss 5G configuration, phosphor choice, and lead times for your requirement.
Frequently Asked Questions
No. It is Exosens’ product name for their latest image intensifier tube, following their 4G and 4G+ families. The formal generational classification of night vision still runs Gen 1 to Gen 3, with everything above Gen 3 consisting of manufacturer designations rather than an industry standard. Compare tubes on FOM, gain, halo, and DRI figures rather than on the number in the product name.
For most professional applications, tubes in the 1800 to 2200 range perform very capably. Above roughly 2400, gains become incremental and cost rises steeply. The 5G at 2500 minimum is aimed at users operating regularly in the darkest conditions, where the extra gain and DRI range change what is achievable rather than simply making a good image slightly better.
Night vision tubes are export-controlled in most jurisdictions, and higher-performance tubes face tighter restrictions. US-manufactured tubes fall under ITAR, requiring an export licence for international transfer. European manufacturers including Exosens operate outside ITAR, which simplifies procurement for non-US customers, though national export controls still apply.