What is F-Stop and Why is the F-Number of the Lens So Important for Thermal Infrared Cameras?

An f‑number (ƒ/#) or f‑stop refers to the ratio of a lens’s focal length to its aperture’s diameter (lens opening vs focal length) and indicates the amount of IR energy (heat) coming through the lens to the infrared sensor. The lower the f-number the larger the aperture diameter, meaning more thermal IR energy is reaching the infrared sensor.

LightIR 16-180 mm f/3.6 MWIR Zoom Lens

Thermal Camera/Infrared Digital Imaging Thermometer

PI 1M: IR cameras for the metal industry - Optris

TiX501 High Resolution Thermal Imaging Camera

Can You Use an Infrared Camera to Detect a Fever?

A Simple Explanation of Aperture - Infrared Conversions, IR

Why is Aperture Measured in F-Stops?

Infrared camera series ImageIR 9500 series

What is F-Stop, How it Works and How to Use it in Photography

What is F-Stop, How it Works and How to Use it in Photography

SupIR 15-300 mm f/4.0 MWIR HD Zoom Lens

PDF) Variable Cold Stop for Matching IR Cameras to Multiple f

Detailed laser processing with F-Theta lenses

OEM Thermal Camera Modules & Components