I think the issue was someone confusing UV and IR filtering.
Glass will block most infrared light but wont block most ultraviolet light. This is the reason the lenses for IR cameras are so hugely expensive as they cant be made from glass :)
UV filter
I think the issue was someone confusing UV and IR filtering.
Glass will block most infrared light but wont block most ultraviolet light. This is the reason the lenses for IR cameras are so hugely expensive as they cant be made from glass :)