What is the purpose of an IR filter in a camera???

Question

What is the purpose of an IR filter in a camera???

Answer 1

Do you mean the one that sits inside the camera covering the matrix?

It's there to filter out the infrared rays, and only leave the visible light to hit the sensor. Infrared is almost always present in one form or another, but we don't see it with our eyes, so in a highly IR-polluted places, when you take a picture, you may end up seeing things you didn't want to photograph. The IR filter takes care of them...

It does not cut 100% IR though, so you may still do Infra Red photography by mounting an IR filter on your lens. That one acts opposite - it cuts all natural light leaving just infrared waves. But because IR light is usually weak and it is being filtered by the camera - you most likely will need long exposures of several seconds to several minutes to capture an IR image.  So a tripod will be a must....

This is what an infra red image may look like:

http://www.dimagemaker.com/ktml2/images/...

(or google for infrared photography for more samples)

LEM.