I don’t know too many people that love to get up in the attic or climb under the house to run cables. In fact, I would venture to say that I don’t know anyone that enjoys this project. However, it is a necessary part of installing a camera. In an attempt to avoid running cable or making permanent alterations to the home, I have been asked on many occasions, “Which camera would work best behind a window?” The fact is there is no good way to put a camera inside your home and point it outside. During daylight hours it is possible but still offers some challenges. After dark all that it is… well… out the window.
Have you ever tried to look out into the dark when the lights inside the house are on? Instead of seeing outside, you probably saw a reflection of yourself. In much the same way, your camera will see a reflection of itself.
Then, did you find yourself cupping your hands around your eyes and pressing them against the glass to eliminate the glare. You have just made an IR gasket, the same gasket in every IR camera. It’s there to keep the IR light produced by the camera from hitting the protective glass and reflecting back into the lens.
Now think back to your last trip to the aquarium. Did you ever take a picture of any fish behind the glass walls of their tank? If so you know that you took a really nice picture of a fish and your flash. The light from an IR camera behaves the same way. Like the flash, the infrared light from an IR camera is an intense light that tends to reflect and glare on glass surface.
Unfortunately, as long as there is more light behind the camera than there is on the other side of the window, you have just created a mirror (See the picture for an example). The best solution in every case is getting a weatherproof camera and mounting it outside.