Porro binoculars

Porro binoculars are wider than roof prism binoculars, because the lenses and prisms are shifted relative to each other. The light goes through a binocular N-shaped nodule through the binoculars. Porro binoculars are easier to produce and therefore cheaper. Porro binoculars offer a little more depth perception than a roof prism binoculars. One disadvantage is that porro binoculars are less compact and often have external focus, which allows dust and water to come into viewer.