Generation I
It started with electrostatically focused Generation I tubes featuring high image resolution, a wide dynamic range and low noise

Generation II
Introduced the Micro Channel Plate for much higher gain in the 1980’s. The original image resolution was less than that of the first generation intensifiers but the gain was much higher up to 30000 fL/fc

Generation III
In the late 1980’s an Image Intensifier with a GaAs photocathode was developed showing an enhanced sensitivity in the Near-Infrared. In the late 1990’s Gen III tubes with improved performance appeared on the market. These types are called Gen III Omni III and Gen III Omni IV.

Generations do not provide a quality level - they only provide information about the production methodology. What matters is the performance of the tube, not the technology.