Roof prism binocular

With a roof prism binoculars, the lenses and prisms are placed right after each other. The prisms are placed in a special way and therefore an almost linear beam of light is possible. The viewers are therefore compact in size and are slimmer than a porro binoculars. An advantage of a roof prism binoculars is that this type, due to internal focus, is less sensitive to dust and water.