how do infrared cameras work? Why can they see infrared light but we cant? What’s different in the lens of a camera to the lens in our eye?
In: Technology
Basically the parts of the camera that detect and convert light into an image are tuned to the wavelengths of the infrared spectrum. The reason we can’t is simply because we never adapted to be able to see it, most likely because we adapted for long range vision with a large depth of field, and infrared generally doesn’t travel extremely far unless it’s from something like the sun.
As for what’s in the lens that’s different, the obvious answer is that the lens of a camera is made up of materials that aren’t found in our lens. But other than needing to be made of a material that isn’t glass (glass absorbs most wavelengths of infrared) there isn’t anything super special in the lens that lets it “see” infrared.
There is something called the light spectrum. This is a range of light we can and cant see.
Normal colours etc is in our visible spectrum that our eyes can actually see.
Infrared in the light spectrum is something we can’t see but SOME of our camera sensors can and is able to make it visible to us somewhat in the way it captures i
Infrared cameras have little pixel sensors to detect infrared light, as opposed to visible light in a normal camera. The lens works similarly, but traditional lens glass absorbs IR light and so a special glass must be used.
Our eyes have four different kinds of cells for detecting light. These cells use chemical reactions that detect specific frequency ranges of light. When a normal camera is made, we try to give it three sensors to mimic the three cells/frequency ranges in our eyes that detect color. Thermal IR is beyond the range of what eye chemicals can detect, and so we can’t see it.
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