Bushnell 10 x 25 Binocular

Optical consequences of the design are that roof prisms are more expensive to manufacture than porro binoculars of the same quality and require phase distortion coatings to eliminate the reduced contrast and sharpness caused by phase distortion a roof prism phenomenon.

Roof prisms also produce a more photographically normal depth perception than porro prisms because the lens barrels are in line with the eyepieces.