How does the long EFL with large optics capabilities affect the DRI?

How does the long EFL with large optics capabilities affect the DRI?

How does the long EFL with large optics capabilities affect the DRI?

The focal length determines the field of view (FOV) of the thermal imaging camera. The longer the focal length, the smaller the FOV, which translates into more pixels across a target at a fixed range (meaning, the target angle divided by the IFOV angle).