The objective lens of a thermal scope typically has a germanium coating that is transparent to infrared light and can be quite expensive. The size of the objective lens can impact the amount of thermal radiation that is collected and focused onto the sensor, which can affect image quality
A larger objective lens can increase the detection range of a thermal scope, allowing for the identification of smaller targets at greater distances. Additionally, a larger objective lens can provide a wider field of view, allowing hunters to scan larger areas and track moving targets more easily.
However, as previously mentioned, larger objective lenses can also make the scope heavier, bulkier, and more expensive. Hunters should carefully consider their specific needs and preferences in terms of image quality, field of view, and detection range when choosing a thermal scope with an appropriate objective lens size.