This History of Infrared Thermography.

https://www.nachi.org/history-ir.htm

Check out this beastly camera used by Signal Corps during the Cold War. It featured a 100-inch infrared lens that was capable of seeing through over twenty miles of hazy air — perfect for capturing reconnaissance photographs of enemy strongholds. The camera was so massive that it required two people to operate: one to frame the shot, and one to snap the photo. 100-inches is 2540mm and the camera appears to use 4×5 large format film, so the equivalent 35mm focal length of this cannon-like lens is roughly 760mm.

John authored the article BTW. Excellent work John.