Simple Explanation of Night Vision Models Differences

DISCLAIMER: The information provided in this article is a simplified explanation of the consumer qualities of the Night Vision devices sold by Basic Precision rather than a detailed technical paper. We omitted from our comparisons outdated Gen-1 devices and aviation-grade NV devices designed for an aircraft application. The data is provided for an average typical device of each generation of Night Vision.

THE SIMPLEST EXPLANATION:

A LITTLE MORE TECHNICAL DETAILS:

	Gen-2	Gen 2+	Photonis	Gen-3	Gen-3+
GAIN - the number of times a NV device amplifies light	10,000	25,000	30,000-50,000	40,000-70,000	60,000-80,000
Signal-to-Noise-Ratio (SNR) - influences the ability of an NV device to distinguish shades of darkness. The higher - the better!	up to     20	up to     25	up to     30	up to     35	up to     40
Resolution - the ability of a night vision device to distinguish the image details which are close to each other. It influences the image clarity. It is measured in lp/mm. The higher - the better!	45-54	52-64	64-78	64-72	64-82
Life Expectancy (a/k/a MTTF) in Hrs. of operation	10,000		12,000 to 15,000

A FEW MORE EXPLANATIONS:

Gen-2

Generation-2 night vision devices, unlike Gen-1 devices, can operate passively with no IR illuminator required. They intensify available light coming from the stars and moon 10 times more than Gen-1, making a scene visible to the human eye. IR illuminator may be used when operating in complete darkness. They produce a cleaner and brighter image with no “fish-bowl” effect. Typical basic spec.: Gain-10,000x; SNR < 20; Resolution 45-54 lp/mm; life expectancy 10,000 Hrs.

Gen-2+

Newer technology, used in Generation-2+ night vision devices allows 2.5 times better light amplification than Gen 2 with better resolution and higher Signal-to-Noise ratio. All of these improvements ensure a better quality of the image with less noise and a brighter picture. Typical basic spec.: Gain-25,000x; SNR < 25; Resolution 52-64 lp/mm; life expectancy 10,000 Hrs.

Photonis

Night Vision devices built with Photonis tubes stand apart from the standard generation-based classification. Although some sources consider Photonis tubes as Gen-2+ devices, Photonis developed its technology in a different way, creating unfilmed light intensifying tubes with extremely clear images and Automatic Brightness Control. In fact, every parameter of a typical Photonis tube is higher than the same number for a typical Gen 2+ device. And the resolution of Photonis tubes is higher than or equal to the typical resolution of Gen-3 and Gen-3+ devices.  Typical basic spec.: Gain-up to 50,000x; SNR < 30; Resolution 64-78 lp/mm; life expectancy 12,000 – 14,000 Hrs.    

MIL Spec grade Gen-3 Thin-Filmed

This technology is a significant step up from Gen 2+. It is often used by militaries. Gen 3 devices handle low-light conditions better than Gen 2+. They provide cleaner and brighter images being better in every department including increased tube life expectancy. Typical basic spec.: Gain- up to 70,000x; SNR < 35; Resolution 64-72 lp/mm; life expectancy up to15,000 Hrs.   

 

MIL Spec grade Gen-3+ Unfilmed

This is the best night vision technology developed to date, and it is often used by special ops. Gen 3+ Unfilmed devices provide the cleanest and the brightest images with the best resolution. They also handle low-light conditions better than any other generation of night vision. They have the longest detection and recognition ranges and are the most reliable and very durable. Typical basic spec.: Gain- up to 80,000x; SNR < 40; Resolution 64-82 lp/mm; life expectancy 12,000 – 14,000 Hrs.     

OPTIONAL FEATURES:

Auto-Gating

This is often the most confused optional feature of NV devices. The myths say that Autogating can protect NV devices from bright light, including daylight. It is not so. Autogating is intended for a different purpose. It is a feature designed to automatically limit the amount of glow coming from light sources. Autogated devices are essential for operating in areas where occasional or regular light pollution may occur, such as military combat, a law enforcement operation in a city, or hunting near a lit road or a lit property. An NV device without Autogating will not allow seeing what is going on behind a streetlight, since the amplified glow of the streetlight is too bright to allow a human eye to distinguish a darker background scene. An Autogated device is a game changer. Most Photonis, Gen-3 and Gen-3+ tubes are Autogated.

With all this said, NV devices which are not geared with Autogating are very suitable for operating in areas with no light pollution, such as hunting in remote locations. In fact, if a hunting scene does not have any source of light pollution, a device with no Autogating may slightly outperform a device of the same class with Autogating on board. An Autogated device may try to soften the glow from the brightest element of the scene - a reflection from a hiding game’s eyes. This reflection would be more distinct if a non-Autogated device is used.

Manual Gain Control aka External Gain Control (EGAC)

This feature allows operators to manually adjust the light amplification of a night vision device. Turning the gain down from the maximum level, will dim the image to the operator’s comfort level in a bright condition like a full moon or snow.

Automatic Brightness Control (ABC)

This feature automatically reduces the image intensifier’s brightness under dynamic lighting conditions. It may extend a tube life by limiting bright light picks amplification within reasonable limits. Automatic Brightness Control also protects the user from temporary blindness caused by an excessively bright image produced by a night vision device when unexpected light pollution of the operating scene happens - the image gets brighter for a split second and then dims to a pre-set comfortable level.

Good Example of How All Three Features Can Work in One Device

The above three features are very often confused with one another. The following example will clarify the difference: If a night vision device has all three features on board (Autogating, Automatic Brightness Control, and Manual Gain Control), then an operator can adjust image brightness with the Manual Gain Control to a level of personal comfort. The Autogating will automatically reduce the glow of any lit object on the hunting scene like a lit feeder light. This will allow an operator to better distinguish objects in immediate proximity to the light. If your hunting buddy unthoughtfully points a flashlight to your face, Automatic Brightness Control will quickly reduce the brightness to the level you pre-set earlier with the Manual Gain. These features can be even more useful in a night combat situation or during an urban night law enforcement operation.   

 

Please do not hesitate to contact us with any additional questions you may have.