Inferred camera

Why is it so expensive ? 1500 dollars for a common inferred camera is really high price. I would agree to that price if it is a high piece of technology or it require special materials to built but those are not the cases. Technically, every common camera can see the inferred light, the only thing you need to do is removing the inner-built filter and use a dark piece of film to block all the other light. The next step is attach two red-inferred LED together with length so that it into the object and ...woalla! Mission succeed. Apparently, some people had thought of this idea and made a really cheap inferred camera on amazon.