Wide angle lenses capture more light than a flat lens because light coming from the sides can still impact it and be refracted. The peephole lens then condenses all of the light it collects down into a tiny stream that is then fed into the eye of whoever is looking through it.

What is spy hole in doors?

A door spy hole offers extra security for a property, as they can be used to see who is at the door before opening for greater personal safety. Door viewers are available in several finishes and colours to complement the colour or finish of a front door.

How does a digital door viewer work?

The Digital Door Viewer (DDV) is a digital peep hole, it has a built in camera which allows you to take time stamped pictures or record anyone approaching your door. … Also when the door bell is pressed the camera will automatically take a phone of who ever is outside, the photo is then stored automatically.