One of the mysteries of the English language finally explained.
1A reflecting prism in which the light is reflected on two 45° surfaces and returned parallel to the incoming beam.Compare with roof prism
- ‘Two porro prism binocular models are new, the 8x42 mm and the 10x42 mm.’
- ‘While not as sexy as a roof prism, the porro prism is a dependable unit made for the outdoors.’
- ‘Modern roof prism designs are capable of performance just as good as a comparable porro prism design, due to current technology such as phase coating and improved reflective backing materials on the prisms.’
- ‘In binoculars, it has added porro prisms to its line.’
- ‘Bushnell's latest couples a waterproof 8x36 porro prism center-focus binocular with a laser rangefinder.’
- 1.1 A pair of binoculars using two Porro prisms at right angles, resulting in a conventional instrument with objective lenses that are further apart than the eyepieces.
Named after the Italian scientist Ignazio Porro (1801–75).
Top tips for CV writingRead more
In this article we explore how to impress employers with a spot-on CV.