How you determine the quality and price of an I2 night vision unit is tied directly to the image intensifier tube inside. Manufacturers produce different generations of tubes that affect the kind of image you get through your night vision device. There is a glossary worth of detailed stats and technical terms associated with differentiating different levels of night vision. But we'll keep things simple here.
The most basic level of night vision. These units are clearest in the very centre of the image, and require a significant amount of ambient light to provide reasonable enhancement. These tubes often benefit from use with an infrared illuminator that can act as a floodlight only visible through night vision.
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Provides a much clearer view with none of the distortion associated with first generation night vision. This level is often popular with home users or security companies looking to add a basic night vision component to their toolset. Gen 2 units will often benefit from an IR illuminator, particularly at farther ranges or when ambient light is low.
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The kind of night vision you can wear all night. Gen 3 units use a substantially higher grade tube that results in less specking and noise than lower models. Generation 3 devices usually have a wider depth of field, requiring less manual adjustment between close and far images. These units often allow the user to choose between manual gain or automatic gain. Manual gain allows the brightness of the image to be adjusted depending on ambient light available.
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Most night vision companies do not use the Gen 4 label, but will instead refer to enhanced Gen3+ models. These use the very best quality tubes which come direct from ITT the manufacturer for over 25 years. These units are also available with the auto-gating feature. Auto-gating prevents a night vision device from flaring to excessive brightness when a source of light suddenly appears. By rapidly turning the unit's photocathode on and off, the image can automatically adjust to maintain visibility even when bright lights appear abruptly.
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A new generation of image intensified night vision has arrived on the market. Instead of using the traditional green hue, white phosphor units translate the enhanced into in a black and white form. This can often help with contrast and depth perception, and can be compared to Gen 2 and Gen 3 green night vision. It is important to understand that White Phosphor does not detect heat like thermal does. It is still amplifying existing light, only in a different colour scheme.
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