What is F-Stop and Why is the F-Number of the Lens So Important

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.

F-Number Explained: Aperture Mastery

Why does the aperture number increase with focal length? What would happen if the aperture diaphragm was disabled and focal length was increased? - Quora

Solved The f-Stop of a Lens The f-Stop of a Lens The

What Is the F-Stop and Why Is It Important in Photography?

Aperture and F-Stops Explained - Outdoor Photography School

Are aperture and f-stop the same thing? - Quora

Stops, Pupils, and Apertures

What is the difference between focal length and aperture? - Quora

What is f-stop on a camera?, F-stop photography

What does the F Stand for in F Number and F Stop? – Sean J Connolly Photography