These calculations appear to use the simplified h=f*tan(Theta) equation. As you've mentioned, this doesn't work for fisheye lenses. I would extend this comment to include any wide-angle lenses with distortion, such as 2.8mm~4mm lenses. If you want to see how distortion impacts camera FoV, you can use another free online calculator:
New CCTV lens calculator with 3D graphics, DORI and DB
in Installation Help and Accessories
Posted
Awesome calculator and graphic interface!
These calculations appear to use the simplified h=f*tan(Theta) equation. As you've mentioned, this doesn't work for fisheye lenses. I would extend this comment to include any wide-angle lenses with distortion, such as 2.8mm~4mm lenses. If you want to see how distortion impacts camera FoV, you can use another free online calculator:
https://commonlands.com/pages/fov-calculator